|English||Spanish for "Dark Zero"
Japanese for "Black Hollow Flash"
Cero Oscuras (黒虚閃 (セロ・オスキュラス), sero osukyurasu; Spanish for "Dark Zero", Japanese for "Black Hollow Flash") is a variation of the Cero technique used by Ulquiorra Cifer in his Resurrección and Resurrección: Segunda Etapa, Murciélago.
The Cero Oscuras is far more powerful than an average Cero, with a vast range and massive attack power. It shattered Ichigo Kurosaki's entire Hollow mask, critically injuring him in the process, and destroyed half of the dome over Las Noches. Though the only Espada who has utilized this technique so far, Ulquiorra told Ichigo "This is the power of a released Espada, the black Cero" and referred to it as "our Cero".