Yui Ootsuka

Yui is a girl with a blonde medium bob cut, and the main protagonist of Shishunki Bitter Change. After an accident in fourth grade, she switched bodies with a boy named Yuuta. Now, Yuuta has become "Yui". "Yui"/Yuuta is lively, cheerful, and makes friends easily. Yuuta was the eldest son in his original family who took good care of his younger brother, and he/she quickly reconnects and becomes as "Yui-nee-chan" his unofficial big sister.

She adapts much more readily to the change and eventually develops doubts if she still wants to return to her old body.