Description- Sekido, a 3rd year student in Kimetsu High School. Sekido is always in a constant state of vexation, irritation, and rage, even towards his brothers. He is the oldest of quadruplets, and has a part time job after school to afford for living expenses. He’s a very hard worker and doesn’t let anything get in the way of his work. He has three other brothers as well: Karaku, Aizetsu, and Urogi. He looks almost identical to his brothers that it’s hard to tell them apart.