"Live well, age well, and go bald well. And die after me. And... if you can, die smiling. If I can't, I won't be able to face Masaki. Don't hesitate to act. Sadness is a cool thing to shoulder, but you're still too young."
Isshin is a tall, muscular man with spiky black hair and brown eyes. He has thin facial hair around his mouth and on his cheeks. As a doctor, Isshin usually wears a white lab coat over his otherwise more casual shirt and trousers. He has the appearance of a man in forties, as noted by his daughter, Karin.
As a Shinigami, he wears the standard Shinigami Shihakushō, along with a tattered captain's haori, worn like a sash and fastened over his left shoulder. The Division insignia cannot be seen as the haori is worn presently.
When he was the captain of the 10th Division, Isshin wore the typical Shinigami uniform, with a sleeveless captain's haori. He had noticeable sideburns, did not have facial hair at the time, and had slightly shorter hair.
Isshin typically acts in a goofy, energetic, and fun-loving manner. Loud voice, big smile and a wide range of facial expressions are his trademark features. He's prone to attack his son all of a sudden for every reason, from being late for a dinner to simply waking him up. Like he claims, it was all to make Ichigo stronger, which actually paid off. Sometimes Isshin can be the life and the soul of the party as shown during the festival in Karakura Town. Initially starting the fun with his daughters he finally took almost all of Ichigo's friends with him.
During his time in Gotei 13 Isshin was a lazy and carefree captain who often tried to make his subordinates do his work for him. For this reason he was in bad terms with Rangiku Matsumoto who was often forced to call him back to order. Isshin was delighted seeing how diligent Tōshirō Hitsugaya was doing all the paperwork and, on the spur of the moment, saw the future of his division in him.
Isshin has also a perverted and lecherous side. He loved commenting how Rangiku's boobs were shining from sweat and bullying Ichigo that his sisters, who were piggybacked by him, weren't wearing underwear. However, when he encountered naked Masaki, he blushed and demanded her to not act casually while looking like that.
One day, about twenty years ago, Hitsugaya reported the death of a Shinigami in Naruki City two months ago, and Isshin expressed knowledge of the incident, fully aware the Gotei 13 was already investigating the incident. When Hitsugaya further reported two more individuals had died within the past month alone, Isshin, concerned with the disappearances, decided to investigate them alone, knowing Rangiku and Hitsugaya were not strong enough to assist him.
Making his arrival known to his division members, Isshin sent them away so he could take care of the mission himself. As Isshin patrolled the area waiting for any sign of danger, he felt the presence of something. Witnessing it killing the members of his division he had previously told to leave, he came face to face with the creature.
Facing the creature, Isshin noted with confusion it was a black Hollow. As the creature roared, Isshin, observing its closed Hollow hole, stated its Reiatsu was still that of a Hollow. As the creature lunged at him, he, blocking the blow, thought to himself even though the creature's appearance was that of a Hollow, it felt like he was fighting a Shinigami. Spotting a Shinigami nearby, Isshin told them to run as the creature charged a Cero between its horns. Stating it cannot be a Hollow, as that is not how a Menos fights, Isshin, lunging at the creature, asked it who was pulling the strings to prevent Soul Society from knowing of its existence. Stating he does not care, Isshin released his Zanpakutō, Engetsu. As he prepared to attack the Hollow, Sōsuke Aizen cut him from behind.
Aware it was not the Hollow who cut him, he began calling out to the Shinigami who did to come out of hiding. Forced on the defensive as the Hollow continued to attack, he, noting the wound was preventing him from using Bankai, launched an explosive attack which severed one of the Hollow's arms. Despite this, the Hollow continued its offensive, pinning Isshin down, and prepared to fire a point-blank Cero at him before someone interrupted the fight. Watching on, Isshin stated the Hollow's new opponent was an "idiot" for seemingly letting down her guard.
Watching as the girl defeated the Hollow, he saved her when it began to self-destruct. Afterwards, he and Masaki introduced themselves, with Isshin taking a liking to Masaki. Later, he returned to Soul Society to report to Genryūsai Shigekuni Yamamoto about what happened. Though Yamamoto overlooked his violation of rules because he kept the damage and casualties to a minimum, Yamamoto suspected Isshin was hiding something, which Isshin denied.
Later, Isshin decided to return to the Human World without permission. While there, he ran into Ryūken Ishida, saving him from a Hollow. After casually greeting Ryūken, he, shown the condition Masaki is in, was horrified he was the reason she was suffering. As tensions grew between Ryūken and Isshin, Kisuke Urahara, stepping in, stopped the fight, stating he knew how to save her.
At the Urahara Shop, Urahara, explaining Hollowfication to Isshin and Ryūken, explained the solution, but as he did, Isshin agreed to sacrifice his Shinigami powers to save Masaki. Afterwards, he entered Masaki's inner world to confront the Hollow. After saving her, Isshin was forced to remain in the Human World. With Urahara's help, he was able to properly adjust to this new world and ultimately open his clinic.
Over ten years ago, Isshin encountered an imperfect Arrancar. He married Masaki, and they had three children: Ichigo, Karin, and Yuzu. Masaki was killed by the Hollow Grand Fisher when Ichigo was nine.
Agent of the Shinigami arc
When Ichigo returns home late after helping a Plus, he is attacked by Isshin, who tells Ichigo dinner is at seven o'clock every night and no matter what the reason is, he will punish anyone who disrupts the household's harmony. As the two argue about being able to see spirits, Karin interrupts. As Isshin uses the opportunity to pin Ichigo to the ground, Ichigo, shrugging him off, goes up to his bedroom. While Karin blames Isshin, Yuzu explains how Ichigo has been seeing more ghosts lately. Surprised Ichigo talks about such things to her, Isshin states Ichigo does not tell him any of his troubles, prompting Karin to say she would not talk about her problems with a father who is over forty, but has child-like communication skills. Turning to the poster of Masaki on the wall, Isshin, saying their daughters are very cold towards him, blames adolescence. When Ichigo attacks Rukia Kuchiki in his bedroom, Isshin, kicking Ichigo in the back, tells him to not make such a ruckus upstairs. Striking him in return, Ichigo says he cannot help but make a ruckus when there is an intruder in the house. Complimenting Ichigo's counter-attack, Isshin asks Ichigo who he is referring to. While Rukia explains how normal Humans cannot see Shinigami, Isshin, leaving the room, returns to Yuzu and Karin, saying Ichigo kicked him hard. While Yuzu comforts him, Karin tells him he reaps what he sows. When the Kurosaki Clinic is attacked by Fishbone D, an injured Karin tells Ichigo blood had started pouring out of Isshin's back, and he fell. Ichigo rushes downstairs to find a bloody Isshin lying on the ground. The following morning, Isshin, attacking Ichigo while he is still in bed, compliments his son when Ichigo pins him to the ground, telling him he has nothing left to teach him. When Ichigo asks about his injuries, Isshin asks when he got hurt. Outside the clinic, Isshin says it is a miracle nobody was injured despite a truck crashing into the house.
After a major car accident, Isshin, arguing over the phone with a hospital employee who is refusing to transfer the overload of patients, says the employee should tell his boss Kurosaki needs a favor and beds will open right up, and, slamming the phone down, calls the employee a low-level fool. When Ichigo asks if there is anything he can do to help, Isshin tells him to stay in a corner so he will not be in the way. When Yuzu brings Yasutora Sado in to the clinic, Isshin tells Ichigo to carry him. While examining Sado's wound, Isshin, noting it looks like a burn and is bleeding all over, tells Sado he will have to remain in the clinic. When Sado refuses, he tells him not to be stupid because he cannot be fine after losing so much blood. When Sado collapses, Isshin tells Yuzu to prepare a bed for him. The following morning, Isshin rushes into the kitchen to report Sado has disappeared.
The night before the anniversary of Masaki's death, the Kurosaki family holds a meeting. Declaring the meeting open, Isshin decides because he is the chairman, he has the final say in everything. When Karin complains about this, he silences her by appointing her staff director. Appointing Yuzu as lunch staff and Karin as the luggage carrier, he, saying he cut his hair for the anniversary, asks them what they think of it, but they complain it is the same. The following day, as the family walks to the graveyard, Yuzu complains about how the hill they are walking up is tough. Telling her to do her best and not to give in because he is with her, Isshin begins to climb the hill while standing on his hands. As Karin tells Yuzu to ignore him because it will never end if she encourages him, Isshin, saying she is naive and he will not stop even if they do not look, slides past Yuzu with his "Special Daddy Sliding Technique", noting she is wearing polka-dot underwear. Karin kicks him, sending him back down the hill. At Masaki's graveside, while Karin is praying, Isshin declares it is time for the annual "Kurosaki Family Tombstone Domino Rally", with Isshin and Ichigo being the first match. Telling him to stop, Yuzu says he will not get any dinner if he does it. Later, Isshin uses a chicken-shaped whistle to call Ichigo and the twins. Telling him to stop because he can hear him even without the whistle, Ichigo asks him if Karin and Yuzu are there yet, but Isshin, saying he has been blowing the whistle for a while, tells Ichigo if he was the only one whom he was waiting on, he would have left for home without him. When he sends Ichigo to find the girls, Ichigo, refusing, says it is tiring and he should go himself. Grabbing Ichigo, Isshin, asking if his little sisters are not precious to him, decides they will split up search for them. Telling Ichigo to search in one direction, he says he will stay there, prompting Ichigo to kick him. Stating Ichigo broke his jaw, Isshin asks if he looks as handsome as John Travolta like this. Sensing the reiatsu of a Hollow, Ichigo runs off while Isshin wonders what is up with him.
While Ichigo is fighting Grand Fisher, Isshin waits inside a building with Karin and Yuzu while Kon (in Ichigo's body), stays outside. Noticing it has started to rain, Isshin wonders why he has not come in. Opening the door to call him in, he cannot find him. Finding Ichigo at Masaki's grave, Isshin offers him an umbrella. When Ichigo refuses the offer, Isshin repeatedly pokes Ichigo in the head until he hits him back with it. When Isshin notes time has passed quickly, and it has already been ten years since Masaki died, Ichigo says it has only been six years. When Isshin states he was "so close", Ichigo loudly complains about this, causing Isshin to say Masaki can rest easily if she sees him being so lively. When he starts smoking a cigarette, Ichigo says he thought he had quit smoking when Karin and Yuzu were born. Revealing Masaki, when they started dating, complimented him about his hand looking cool when he was smoking, Isshin notes this was the only time she had complimented his looks. As a result, he smokes at her graveside every year on the anniversary of her death. Isshin tells Ichigo not to look so sad. When Ichigo asks why nobody blames him for Masaki's death, Isshin, asking why he would blame Ichigo, says if he blamed her death on him, Masaki would become mad at him. Explaining how Masaki was a woman who would die to protect her son, Isshin, reminding Ichigo he is the one whom the woman he loved gave her life to protect, knees Ichigo in the back, telling him to live his life well, and leaves.
One Wednesday evening, Isshin brings the family to watch Don Kanonji's TV show when it comes to Karakura Town. When an earth-bound Plus begins to howl due to people trespassing on what he views as his territory, Isshin, noticing Karin is annoyed, asks her what is wrong. She tells him it is nothing. Once the show begins recording, when Isshin excitedly tells Yuzu it is starting, Yuzu tells him to be quiet. When Ichigo is stopped by security after jumping across the barriers, Isshin, beginning to cross the barrier as well, is caught by Yuzu, who tells him to stop. After the Earth-bound Plus becomes a Hollow, it shatters many of the hospital's windows, showering the crowd with glass. Asking Yuzu and Karin if they were hit by the glass, Isshin, telling them not to worry about him because he is happy to die for their sake, collapses.
Later, after Karin is protected from a Hollow by Sado, she brings Isshin to the spot where she left him so he can help the injured Sado. When he does not see Sado, Isshin, speculating Karin lied about the injured man so she could spend time with him, for he has been busy with work, rips open his shirt, telling Karin to jump into it. Punching him in the face, Karin pins him to the ground. Asking why she is pinning him in such a painful position, Isshin wonders if it is a new way of expressing familial love.
When Ichigo and his friends gather for a fireworks festival on August 1st, the rest of the family, all wearing kimonos, come running up to Ichigo, knocking him down. Noticing the girls' behavior, Ichigo asks if they are drunk. Explaining how a juice seller had used wine to dilute the juice instead of water, Isshin tells the group they saved a seat on the opposite bank of the river that morning after giving up on the idea of sitting in a boat on the river because the police would catch them. Isshin invites Orihime Inoue and Tatsuki Arisawa, calling them "cute girls". When they say they will catch up later, Isshin heads off with the twins and Ichigo's other friends. Later that night, when Ichigo complains to a drunken Isshin about having to carry Karin and Yuzu, Isshin, telling his son he can enjoy that touch, reveals they did not wear any underwear under their kimonos. When Ichigo angrily asks him what he wanted to do to his daughters, he states it is just a joke, and he should not make such scary expressions. When Ichigo tells him he will be leaving for another week again and might not be back until the summer vacation ends, Isshin tells him if he meets any good girls, he should remember to introduce them to him. When Ichigo looks at his father, Isshin, asking why he is giving him an "I'm very worried about what will happen when I'm gone look", tells Ichigo he will take care of everything at the house, and while he is still around, he will not allow anyone to hurt his family. When he notes what he just said was cool and is a useful sentence, Ichigo, asking if he is an idiot, says he is not worried at all. When Ichigo leaves for his "trip" during his summer vacation, Isshin, once again trying to assault him, misses, smashing his head into the pavement in the process. When Ichigo dismisses it, Isshin, giving him a protective charm, tells him Masaki gave it to him, and it will bring him good fortune. Isshin tells him he is lending it to him for his trip, and he has to give it back when he returns. When Ichigo does not answer, Isshin tells him he will have to shave his beard if he loses it.
Soul Society arc
During Ichigo's final fight with Byakuya Kuchiki, the Hollow inside him completely awakens and takes over control of Ichigo's body. When that happened Isshin's reiatsu could no longer suppress the creature and the reishi string, which was binding Hollow's soul with his Human Shell, finally broke resulting in returning Isshin's Shinigami powers to him.
When Ichigo returns from Soul Society, Isshin attacks him in bed. Ichigo blocks the attack, earning praise from Isshin.
Bount arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.
Click "show" to read the arc plot.
After Ichigo returns from his "summer vacation", Isshin resumes his normal antics of attacking Ichigo. While Ichigo initially ignores his attacks, he gets annoyed enough to pummel Isshin. At breakfast, when Yuzu asks Isshin what happened to his face, Isshin, turning around, says nothing happened. As Ichigo asks Yuzu and Karin about their summer, Isshin, getting up from his chair, kicks Ichigo in the face, knocking him backwards. As Isshin mocks Ichigo for not being able to react fast at all, the two of them begin fighting.
Later, after Ichigo returns home from school, Karin greets him, and Yuzu tells him he is just in time for dinner. Beginning to fight with Ichigo again, Isshin tells him he is late. When Yuzu tries to stop this, Karin tells her to leave them alone and think of it as a bonding experience for the two of them.
When Ichigo returns the protective charm to Isshin, he, saying he does not want it, sews it into Ichigo's school uniform. When Ichigo asks if he lied about Masaki having given him the charm, Isshin changes the subject.
When Grand Fisher is about to attack Kon (who is in Ichigo's body), the charm Isshin gave Ichigo is activated, creating a barrier between them. Wearing a Shinigami uniform, Isshin, telling him to take it with him wherever he goes, turns his attention to Grand Fisher, telling him Ichigo is not home and he should play with him instead. When Grand Fisher questions who he is, Isshin, apologizing, introduces himself. Hearing the name Kurosaki, Grand Fisher realizes Isshin is the father of Ichigo. Confirming this, Isshin, throwing the charm to Kon, addresses him as Kon. When Kon asks how long Isshin has known about Kon taking Ichigo's place, Isshin, revealing he has known since he saw him enter Ichigo's body in the graveyard, further notes he has never called him by Ichigo's name when he was in Ichigo's body. Stating he has no interest in Isshin and he only came to kill Ichigo, Grand Fisher orders Isshin to hand him over. When Isshin reveals he does not know where Ichigo is, for Ichigo is no longer a kid and he had always been very relaxed with the rules in his house, Kon stating he is very strict with Yuzu and Karin. stating girls and boys are very different, Isshin tells Grand Fisher he came to kill him.
Laughing, Grand Fisher, asking if they believe he is nothing, but a regular Hollow, transforms, growing in size. As a shocked Kon says Grand Fisher is nothing like the Menos he saw before, Isshin reveals that Grand Fisher is an Arrancar, a Hollow who has removed his mask to gain Shinigami powers. Drawing his huge Zanpakutō, Grand Fisher, stating the size of his sword shows the amount of power he has, says Isshin cannot win with his twig-sized sword. Smiling, Isshin, challenging Grand Fisher to give it a try, draws his own Zanpakutō. After Isshin and Grand Fisher clash, Isshin states all captain-level Shinigami consciously keep their Zanpakutō in a manageable size, or else everyone would be swinging around swords the size of skyscrapers, telling him to remember never to judge an opponent by the size of their Zanpakutō. As Grand Fisher falls, Isshin, saying he should not talk about a Shinigami's strength until he can understand this, calls him a kid.
Appearing, Urahara asks if Isshin had his revenge. Stating it has been a long time since they saw each other, Urahara says he is relieved he seems well. When Isshin asks what he is on about, Urahara says it would be problematic if he had become weaker and blamed him for it. Isshin states rather than blaming him, he would simply accept it if he became weak. When Urahara asks how it feels to take the form of a Shinigami after abandoning it twenty years ago, Isshin states it is "so-so". When Urahara asks if his heart is now free of guilt, Isshin, stating he never hated Grand Fisher or any Hollow like that, reveals the thing he has not been able to get over during the last twenty years is his inability to save Masaki that night. Urahara says he has not changed and his attitude is similar to his son's, which Isshin denies. Noting the Visored have contacted Ichigo, as Urahara predicted, Isshin explains how they are a group of ex-Shinigami who used forbidden spells to acquire Hollow powers, and they never found their base of operations or learned their goals. When Urahara notes their contacting of Ichigo, Isshin says they are preparing for the battles ahead, just like they are doing. Telling Urahara they must have noticed the sudden growth of the Arrancar, Isshin, stating Grand Fisher was on a completely different level than the pseudo-Arrancar they had seen before, notes Aizen, using the Hōgyoku, must be responsible for their sudden growth. Noting Grand Fisher's reiatsu was imperfect, Isshin concludes he was only an incomplete prototype, created to test how it performs in combat. Isshin says Aizen will finish his research soon and lead an army of Arrancar to take over the Menos Grande before destroying their world.
When Ichigo returns home from school, Isshin elbows him in the face, knocking him to the ground, surprising Isshin, who notes he looks depressed. Saying he must have done poorly in an exam, he tells him Isshin "The Man" Kurosaki does not get upset by school exam results, saying grades are unimportant. He tells Ichigo a high school student should be energetic and do things which are difficult to speak of, such as falling in love. When Ichigo says he will stay in his room until dinner, Yuzu blames Isshin for not apologizing. When Rukia returns to the Kurosaki household, Isshin and Yuzu try to eavesdrop on her and Ichigo from his bedroom door. When Ichigo hears him talking to Karin, he scares them off. When Rukia lies to Isshin and Yuzu about needing a place to stay, leaving Yuzu in tears, Isshin, stating she should be allowed to stay at their house, says Rukia is always welcome. Going over to Masaki's memorial picture with Yuzu, he tells it they now have three daughters. The following morning, when Yuzu tells Isshin she cannot find Ichigo, Isshin asks if Rukia is around. When Rukia, appearing, asks what is wrong, he notes she is alright while Yuzu tells her Ichigo is missing. Later, when Isshin is doing the laundry, he finds Yuzu crying over Ichigo's disappearance. Attaching clothes pegs to his beard, he calls himself a bearded daruma doll. Saying he already is one, Karin pulls on the pegs, knocking Isshin to the ground.
Hueco Mundo arc
When Ichigo leaves for Hueco Mundo with Uryū and Sado, Isshin visits Ryūken Ishida at the Karakura Hospital. When Ryūken, asking how he got in to the training area, calls him Kurosaki, Isshin, noting this is the first time he has called him that, asks why his attitude has changed. Noticing Isshin is wearing his Shinigami uniform, Ryūken asks if his powers have returned. Stating he thinks so, Isshin, wondering if Ryūken is not going to read Uryū's farewell letter, asks him if he let Uryū go. Ryūken states it is none of his business, and it is up to Uryū if he keeps his powers and whether or not he lives. When Isshin says Ryūken is a pretty bad father, Ryūken states he is doing better than him, which Isshin admits is correct. Isshin notices Ryūken still smokes despite being in a hospital, ignoring the "No Smoking" sign right next to him.
The New Captain Shūsuke Amagai arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.
Click "show" to read the arc plot.
As Ichigo wakes up in the morning, Isshin, jumping through his bedroom window via trampoline to greet him, tries to kick him as a way to say good morning. Missing, he falls to to the ground after breaking the window. Later, he, appearing in the kitchen upon hearing his next door neighbor has moved away, he, attempting to kick Ichigo again, is repelled and starts to complain about his injuries.
Fake Karakura Town arc
After Aizen's defeat of the Shinigami captains, Aizen begins to reveal to Ichigo everything he knows about him. He is interrupted by Isshin, who, appearing with his Zanpakutō drawn on the battlefield between his son and Aizen, states Aizen "talks too much". As Ichigo calls out to him, Isshin, turning to his son, headbutts him with enough force to send him flying over to a building, where he, almost falling off the roof, grabs hold of the side just in time. Moving to kick Ichigo off the side, Isshin, looking back at Aizen, retreats with his son. After getting enough distance and finding a place to hide, Isshin holds Ichigo down to keep him quiet, prompting Ichigo to kick him in face. As Ichigo explains how he knows enough to keep quiet - he just could not breathe - Isshin assures his son he is seeing correctly, and he knows he must have a lot of questions, but they need to wait until later. Ichigo surprises Isshin by stating he has no questions and assuming if he kept this secret, he must have had his reasons to do so. When he decides to not force the issue and allow Isshin to explain when he wants to, Isshin compliments his son on talking so competently. Ichigo tells him to think nothing of it because someone else told him something similar, which helped at the time. He thanks his father for bringing him back into a mood to handle the current situation. As Ichigo moves to attackGin Ichimaru, Isshin, going on the offensive, attacks Aizen. When his attack is blocked, Isshin, flicking his finger, sends Aizen crashing through several buildings. As Isshin continues the assault, Aizen, finding an opening, unleashes Hadō 63. Raikōhō on Isshin.
As their battle progresses, Isshin, noticing Aizen panting and becoming less sharp, asks him if he is already at his limit. When Aizen states he has reached his limit as a Shinigami and his soul is being reformed, Isshin asks what he is talking about. Aizen states the will of the Hōgyoku has finally begun to understand what he desires. As Aizen elaborates, Isshin states it still sounds like nonsense to him. As Aizen shocks Isshin with his claims, their conversation is interrupted by Gin smashing Ichigo into a nearby building. When Isshin tries to say something to Ichigo, he tells his father to not talk to him and stay out of his way because he nearly has Gin. When the Hōgyoku begins to envelop Aizen, Ichigo asks Isshin what is happening. When Isshin states he had been thinking to himself he had no idea what was going on when Ichigo flew past them, and he still does not know, Ichigo says he should know because he had been fighting him, prompting Isshin to state he should ask Aizen, who is attacked from behind by Urahara. Shocked, Isshin and Ichigo watch as Urahara and Aizen battle.
After Aizen transforms, Isshin attacks him from behind as he is talking to Urahara. When Aizen kicks his sword away, Urahara and Isshin, attacking him simultaneously, entangle him, allowing Yoruichi Shihōin to attack Aizen from above. After the attack fails when Aizen easily breaks the armor Yoruichi is wearing, Urahara and Yoruichi argue about how the armor, made by Urahara, had failed while Isshin awkwardly looks on. After the fighting resume, Urahara uses the special abilities of Benihime to immobilize and attack Aizen. Just as Aizen tells Urahara such techniques will never affect him, Isshin, appearing right in front of Aizen, uses Getsuga Tenshō to slice the latter down the middle. As the dust settles, Isshin notes Aizen's reiatsu was unreadable, and it was like Aizen was not even really there. Emerging with a large crack in his form's face, but otherwise unfazed, Aizen, stating he understood that attack, declares they will now come to understand his power. After Aizen defeats the trio, he, along with Gin, leaves for Soul Society to destroy the real Karakura Town. Managing to get back on his feet, Isshin, going to a shaken Ichigo, tells his son to open a Senkaimon so they can follow Aizen, reminding him of their job to protect Karakura Town.
When Ichigo says there is no way to defeat the monster Aizen has become, Isshin snaps him out of it by asking him if he plans to let something precious to him be destroyed again. With Ichigo's resolve restored, Isshin and Ichigo enter the Dangai to follow Aizen. After entering, Isshin, noticing Aizen has destroyed the Kōtotsu, decides to take advantage of the warped time-space, telling Ichigo he will teach him the Final Getsuga Tenshō. Explaining to a confused Ichigo the nature of the Dangai's time distortion and its past as a penal colony, Isshin reveals while they are inside the Dangai, time passes two thousand times faster. He reveals it is thanks to Urahara's technological prowess Ichigo's group was only thrown back in time a few days when they went to Soul Society to rescue Rukia rather than hundreds of years. Telling Ichigo he will suppress the Kōtotsu, Isshin embeds four implements, which are attached to his wrists by cord, into the wall of the Dangai. He says that he will use his own reiatsu to hold back the current, which he believes he can do for around two thousand hours, nearly three months. He tells his son to use that time to get information from Zangetsu about the true nature of the Final Getsuga Tenshō.
As Ichigo engages in Jinzen, Isshin tries to hit him, but Ichigo dodges. Stating that being able to dodge proves Ichigo's mind is not inside his sword, Isshin questions if he can converse with Zangetsu. Frustrated, Ichigo tells him he has never gone to his inner world by meditating. Telling him about Jinzen, Isshin notes all the techniques he has obtained thus far were probably obtained by forcing them with sheer power. Later, when Ichigo receives a slash on his shoulder, indicating to Isshin he "did it", Isshin warns him to be careful because this time around, Zangetsu is going to go on a rampage. Recalling his Engetsu was the same way, he notes their Zanpakutō spirits do not want to teach them this technique, and Ichigo will soon find out why. While Ichigo is battling in his inner world, Isshin, slumped over on his knees as his spiritual power is ebbing to its last bit, ponders why Ichigo is still training.
Ichigo later arrives in Karakura Town in Soul Society, carrying an unconscious Isshin, who is sporting a much longer beard. Placing his father on the ground, Ichigo thanks him.
Gotei 13 Invading Army arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.
Click "show" to read the arc plot.
As Kon searches for the missing Nozomi Kujō, Isshin stands in the bathroom. 
Introducing Yuzu, Karin, and Isshin to Nozomi, Ichigo says Rukia is the only relative she has left following the break up of her family. Pleading with Isshin to allow Nozomi to stay with them, Yuzu likens her story to a movie. Granting the request, Isshin says he would do so even if it was not like a movie. Proudly telling the poster of Masaki he now has four daughters, Isshin, comparing the house to a harem, leaves with Karin and Yuzu to do some shopping. Later, when Orihime is invited by Karin to make dinner, Isshin, agreeing, says he will be a father to them all, receiving a thump from Ichigo in response.
The Lost Substitute Shinigami arc
Isshin yells for Yuzu to choose which tie looks better with his suit for her opening ceremony. When she says either one, he reacts comically. Later, he leaves with Yuzu and Karin for school. One day, when he goes to Ichigo's room to wake him up by pouncing on him, Ichigo dodges his pounce, sending him all the way through the window. Bracing himself on the window, Isshin, yelling at his son for letting him go through the window, asks what he would do if he fell and died. When Ichigo states he would just go to Soul Society, Isshin notes Ichigo has finally come to terms with his father's previous occupation. Telling him he would not have died falling from two stories, Ichigo, trying to loosen Isshin's grip on the window, says he is having strange dreams recently because of him, demanding he apologize. When a surprised Isshin asks about his dreams, Ichigo says he has already forgotten about them.
As Ichigo is walking home one night, he spots Isshin meeting up with Urahara. When Isshin seems to notice Ichigo's presence, Urahara wonders what is wrong. When Isshin suggests they move away to have a private discussion elsewhere, Urahara agrees, and they both move away.
Later, at the Urahara Shop, Urahara, finishing with something, says it is the last one, asking if Isshin is sure. When Isshin, saying he is getting annoying, asks how many times Urahara needs to ask that, Urahara states it is a matter of whether or not a parent robs his son of his future, so it is common sense to confirm it several times. When Isshin says he knows and he is sure, Urahara says they will make their final move, and a mysterious figure steps forth. As Urahara states once the Shinigami inserts some of their reiatsu into the large glowing container, they are done, Isshin, looking away, appears upset. Later, Isshin, who is carrying a glowing, sword-like object, walks through the moonlit streets with Urahara.
After Ichigo loses his Fullbring, he is stabbed through the chest. When he looks behind to see who did it, he, seeing Urahara and Isshin behind him, asks if his dad was in on this betrayal as well. Calling Ichigo an idiot, Isshin, saying he did not stab Ichigo, tells Ichigo to look closely so he will see the form of the sword's wielder, which turns out to be Rukia, who stabbed Ichigo to give him his powers back. Afterwards, Ichigo notices his father's power was used to help restore his own. When Orihime and Sado start to break down from Tsukishima's ability, Urahara and Isshin knock the pair out. Isshin catches Sado, and when Urahara catches Orihime, he complains about Urahara getting a better deal out of this than he did. They bring Orihime and Sado to Urahara's shop, and after Tsukishima is defeated, they become stable. They are left in the care of Tessai Tsukabishi and Isshin. Deciding to return to where the battle is taking place, Urahara, telling Isshin to remain behind, acknowledges Isshin's concern about Ichigo learning the truth, stating Ichigo is bound to learn it eventually.
The Thousand-Year Blood War arc
After Ichigo is kicked out of the Soul King Palace, he ends up back in front of his home. When Isshin comes out to greet him, Ichigo flees. Later, Isshin goes to Ikumi Unagiya's home in his Shinigami form to confront Ichigo, and both leave Ikumi's place. After joking around, Isshin, revealing he was told by Urahara about the events in Soul Society, deduces Ichigo was sent back home by the Royal Guard.
Recalling Ichigo once said he should tell him about his heritage when he is ready, he says now is the time. He reveals Ichigo is not a Shinigami, but neither a normal Human. Telling Ichigo his mother was a Quincy, Isshin begins to recall his time as a captain and when he first met Masaki.Afterwards, Isshin also decided to tell Ichigo the true reason behind Masaki's death.
Isshin recalls how he didn't go save Masaki on the day she died, not only because of his own powerless state, but how he believed that she could handle herself. He then explains the Quincy prophecy to Ichigo. He asks if Uryū Ishida ever talked about his family, and explains what happened to Uryū's mother when Ichigo says he doesn't know about it. He then reveals that all Quincy have Yhwach's blood flowing in them, which shocks Ichigo. After this, Ichigo thanks him. As Ichigo walks away, Isshin asks him how he intends to return to the Soul King Palace and witnesses Mera whisking Ichigo away.
Later, he states he will join Yuzu for lunch after he is finished with a patient. 
Kaikyō Kotei (界境固定, Realm Boundary Fixation): Prong-shaped, rod-like devices about the size of throwing knives attached by long cords to bracelets worn around the wrist, two to a bracelet for a total of four. They are thrown into the Kōryū in the Dangai to stop the flow of the Kōryū. Usually, dozens of Shinigami are required to pour their Reiatsu into the current to fixate it, but high level Shinigami can do this without assistance.
Powers & Abilities
Master Swordsman: Despite being rusty, Isshin still possesses great skill in swordsmanship, allowing him to effortlessly slice through Grand Fisher's body and his Zanpakutō with a single swing of his sealed sword. While fighting against Aizen, Isshin used kendō, which he performed very proficiently, breaking concrete into pieces with a single strike.
Agitowari (顎割, Jaw Splitting): A single sword attack which cuts an opponent in half from the jaw down the length of the body until the target is bisected.
Kidō Master: Isshin can create charmed objects to act as a defense against hostile forces, such as the Arrancar Grand Fisher. He can erect powerful barriers which can completely erase any traces of reiatsu.
Shunpo Expert: Isshin is proficient in the use of Shunpo, keeping fast opponents on their toes with his continuous assaults. He evaded a powerful, point-blank Hadō 63. Raikōhō fired by Aizen.
Isshin Flying Double Knee (一心・フライング・ダビル・ニー, Isshin Furaingu Daburu Nī): A flying double knee attack performed by Isshin against his son as part of their usual playful fighting.
Isshin Handstand Dash (一心・サカダチダッシュ, Isshin Sakadachi Dasshu): A simple running handstand used to show his physical capability to his daughters while walking up a hill.
Chōhigezutsuki (超ヒゲ頭突き, Super Stubble Headbutt): A headbutt attack with enough force to send an opponent flying backward a considerable distance.
Oni Dekopin (鬼デコピン, Oni Headpoke): A simple finger flick with enough physical force to send an opponent flying a considerable distance away and through multiple physical constructs.
Immense Spiritual Power: As a former captain and head of one of the Five Noble Houses, Isshin possesses a considerable amount of spiritual energy, but he used to have a greater amount of it before losing his powers. Ichigo and Shinji are able to sense its strong presence from miles away. Kon was stunned by the level of Isshin's power when he watched Isshin kill Grand Fisher with one swing of his sealed Zanpakutō. Using his reiatsu, he can fixate the Kōryū in the Dangai by himself for up to two thousand hours (roughly three months) before it runs out, something which lower-echelon Shinigami come in by the dozens to do under normal circumstances.Masaki Kurosaki described his Reiatsu as "incredibly powerful".
Enhanced Durability: Even without his Shinigami powers, Isshin can take severe physical punishment (e.g. fighting with Ichigo and being kicked by Karin).
Spiritual Awareness: As a spiritual being, Isshin is spiritually aware. He sensed Grand Fisher from a significant distance.
Engetsu (剡月, Scathing Moon): It looks like a ordinary katana, with a red handle and hexagonal tsuba. It is carried on a string wrapped around his belt in an iaidō style, and worn with the edge down like a tachi instead of the edge up like a katana. The hilt's pommel has a blue tassel attached at the end.
Shikai: Engetsu's release command is "Burn" (燃えろ, moero). The sword does not change shape upon release, but its blade is sheathed in a form of spiritual energy, which engulfs the sword's tassels, creating long, trailing streams.
Energy Technique: Isshin can take his blood and spit it onto his sword, doing so activates a large wave of deadly spiritual energy to emanate from the sword and take out his opponent.(Unnamed)
Getsuga Tenshō (月牙天衝, Moon Fang Heaven-Piercer): During his battle with Aizen in the Fake Karakura Town, Isshin used Getsuga Tenshō by gathering spiritual energy in his Zanpakutō's blade and slashing down his opponent. When used against Aizen, Isshin's blast demolished a large radius of the Fake Karakura Town and left behind a huge crater.
Bankai: Not yet revealed. Aizen states it puts a considerable strain on his body, rendering it unusable if he is heavily injured. Isshin himself has noted heavy injuries prevent him from fixing his reiatsu properly, hence why he cannot activate it.
His theme song, as chosen by Tite Kubo, is "Don't Drag Me Down" by Social Distortion.
Before the series started, Tite Kubo was going to portray Isshin as a mortician, resulting in a character he feels looks better in black.
(To Ichigo Kurosaki) "Silence! No matter what reason, to he who disrupts this household’s iron harmony, only a punishment of blood can be rendered!"
(To Ichigo about Masaki Kurosaki) "Around the time we started dating, she said that my hand is cool when I'm smoking a cigarette. Now that I think about it, that was the only time your mom complimented me on my looks. So every year I smoke on this day only. In front of her."
(To Ichigo Kurosaki) "If I were to blame Masaki's death on you, Masaki would get mad at me. It's not anyone's fault that Masaki died. It's just that, the woman I fell in love with was a woman who could die protecting her son. And don't forget, you are the guy the woman that I loved gave her life to protect."
(To Ichigo Kurosaki) "Live well, age well, and go bald well. And die after me. And... if you can, die smiling. If I can't, I won't be able to face Masaki. Don't hesitate to act. Sadness is a cool thing to shoulder, but you're still too young."
(To Ichigo Kurosaki) "I'll take care of everything at the house! While I'm still around, I won't allow anyone to hurt my family. Ah! What I just said was so cool! That sentence is pretty useful."
(To Grand Fisher) "I'm sorry, Mr. Hollow, but Ichigo's not in right now. As a replacement or something, how about playing with me instead?"
(To Grand Fisher) "Even if you have no interest in me, I'm still here to kill you, so if you don't treat me as your opponent it would be a problem."
(To Grand Fisher) "Let me teach you the basics. All captain class Shinigami control the size of their Zanpakutō, otherwise everyone would be swinging around swords the size of skyscrapers like yours. Remember that you can never judge the strength of an opponent by the size of their sword. You should have at least known that much before you challenged me, kid."
(To Kisuke Urahara regarding saving Masaki Kurosaki) "You don't need to make it all so complicated! I've just gotta give up being a Shinigami and protect her for the rest of her life, right?! Of course I'll do it! If I let the girl who saved my life die because of some stupid regrets, I'd have to laugh in my own face!"
↑ 1.01.11.2Bleach Official Character Book Souls, page 37