The Lost One's Weeping (Karma X Demon/Lazy reader)

''My brother died because of me....'' I have always hated myself..Even my parents hated me yet my brother still loves me..I am (Y/n)(L/n). I am known as ''the deadly crimson''.I am no ordinary person, I am a demon.I went to kunugigaoka highschool to kill one certain thing...I was sent on a mission to kill him and there I saw an interesting boy......Why do I feel this way??