Question: who is ulquiorra in bleach?
Answer: Ulquiorra Cifer (ウルキオラ・シファー, Urukiora Shifā; Viz "Ulquiorra Schiffer") was an Arrancar and a member of the Espada. He served as the Cuatro (4th) Espada and was the most trusted Arrancar in Sōsuke Aizen's service.