My sister, who loves words like "conquest," "flags," and "CGs," always behaves strangely. When I observed her out of curiosity, for some reason I became the fiancée of the crown prince. Resenting this, my sister tried to kill me, so I struck back first. This is that story.

My half-sister has always been strange. She keeps muttering things like "flags" and "events," and is always saying things like "You're supposed to be a villainess and bully me!" But even though her behavior is excessive, she's still my sister. There's no way I would bully her. My stepmother consulted with my father about whether we should put her in a hospital, but he got angry and said we shouldn't do such a thing. We ended up enrolling together at a magic academy, but now I spend my days being yelled at by my sister, saying things like "You ruined the event!" and such.