The re-occuring theme of religion makes me think that Aizen (lucifer) is a "fallen angel" (fallen captain) from "God" (Spirit King) and has decended from Heaven (soul society) and become the leader of hell (Hueco Mundo). Maybe he was the Spirit Kings "right hand angel" or main body guard which would explain his superior abilities to all other Shinigamis. Forbidden fruit = Orb that changes people into hollows. How did he evade the spirit king and become a captain in Soul Society? By disguising his true self with his Shikais abilities. Maybe the Aizen we see (if that is his real name) isn't even what he actually looks like.
Aizen has been orcherstrating ichigo's development for his own gain. He know's of Ichigo's Vasto Lorde (I know we aren't 100% sure if his transformation is actually a Vasto Lorde, hense the title "prediction") and wants to control it when he attains it. How? By turning Ichigos mother into arrancar (you heard it here first) and using her to get to him. If not that way, then by using his Shikai's illusionary abilities to trick Ichigo into thinking his mother is on Aizens side.
A quick chart into how I think the evolution works
Shinigami -> Vizard -> Vasto Lord (become more hollow) (Due to I.D./Hollow...Sigmund Freuds theory...Wants nothing but to satisify desire)
Hollow -> Arrancar (released 1/2) -> Vasto Lord (Learn Shikai/Bankai) (Ego/Shini spirit...Sigmund Freuds theory...Governed by prinicpals which allows for logical decisions and concious. This is why some hollows are capable of good. For example...Ichigo's Zangetsu taught him honour and priniciples)
Ichigo's father and Aizen are somehow related. This is how Aizen knew of Ichigo's innate abilitiy
After Aizen is defeated by the Vizard, he will retreat. Then the Spirit Key/Royal guard will interrupt and there will be a battle between everyone
Royal Guard will be after the Vizard/Ichigo for obtaining hollow powers (which will lead to Ichigo's father playing a role who might have been an ex royal guard himself)
Soul Society will be after Aizen/Vizard (this will create internal conflict within Soul Society due to it's close connections with Ichigo)
Ichigo will be after his mother who Aizen turned into an arrancar
Vizard will be after Aizen