Tsumiki Fushiguro

Tsumiki Fushiguro is Megumi Fushiguro's older stepsister in Jujutsu Kaisen.

She's a kind, gentle, and responsible non-sorcerer civilian who basically raised Megumi alongside their mother after their father (Toji) disappeared from their lives. Tsumiki is depicted as a caring, morally upright person who deeply values doing the right thing and looking out for others—even strangers—which strongly influenced Megumi's own sense of justice and his "save the good people first" philosophy.

Without spoiling major plot points: she's an important emotional anchor for Megumi, and her fate becomes one of the driving personal motivations for several key characters in the story.