Yui was Ikari Shinji's mother and Ikari Gendou's wife. She died in an activation experiment of EVA-01 in 2004. She was once a student in Kyoto University and knew her husband and Fuyutsuki there. Her talent in bio-engineering has been noticed by SEELE and later being introduced to work for SEELE. She is the one who develops the theory of Project E and she is also the main bio-engineer of Gehirn. She also introduces his husband and Fuyutsuki to work for SEELE. After she dies, Ikari Gendou is being accused for murdering her and her son ran away from Gehirn. After that, Shinji is left to a teacher in Tokyo-1 by his father until their first meet in 2015.