A Japanese geneticist who opened the Sasaki Institute, a school for young mutants much like the Xavier Academy. At one point meeting Professor Xavier himself, the two had a short lived romance resulting in the birth of Yui's son Takeo.[citation needed]

Some time later she closed her school and continued her research with some of her previous students in an attempt to eliminate mutant powers. She did this out of concern for her son's uncontrollable powers. The results of which was a serum that caused the rapid development of secondary mutation, often leading to insanity.[citation needed]


  • The serum/virus Yui developed supresses mutations. But after some doses, the serum/virus seems lost its effects, making the mutation to return in a really agressive way. This usually results in monstrous transformations and loss of rational cognitive function in the target (Damon-Hall Syndrome).
  • In the sub-basement of her research facility, Yui had a large machine that could scramble any attempt, either telepathically or electronically made to scan for mutants. It seemed to start up upon detecting a scanning attempt and blocked out a large area of Northern Japan.

Discover and Discuss


Like this? Let us know!