Kirika Ueno

Student Body President and classmate of Haruaki. She has two cursed tools. The first, called Ginstrnag's Love, is an article of clothing that prevents the user from dying when worn. In exchange, the user's heart dies and they must wear it forever. The second tool, The River of Black Strings, has the ability to induce the opponent's murderous intents and serial murders and use it against them. She used to be part of an organization called Nightcrawlers. Spoiler The River of Black Strings curses the user to want to hurt or kill somebody. Kirika usually satisfies the curse by killing herself and coming back to life as she wears the Ginstrnag's Love. (Source: Wikipedia)