Kengo Mutou (無桐 剣午, Mutou Kengo) is the biological older brother of Iori Mutou.
Personality
Kengo is a serious and responsible individual. He constantly criticizes Iori about the fact that she always runs away from decisions, causing their relationship to be quite strained. However, he still cares very much about his little sister.
Appearance
Kengo looks very similar to Soushiki Zerozaki, having slicked back hair (although his is short and half-parted to the side) and glasses. He wears a shirt with a blue sweater on top of it and dark blue jeans.
Plot
Soushiki Zerozaki's Human Experiment
While Iori tries to sneak out of the house without being noticed, Kengo catches her and lectures her like always about her future. She listens but doesn't take much to heart, like usual, then runs away. After that, Hatsubame Mutou asks Kengo if he's picking on their little sister, and he tells her that he's just trying to teach her. Later, Kengo becomes one of Tokei Tokinomiya's puppets, along with the rest of his family besides Iori. When she comes home, she is ambushed by the puppets, and puppet Kengo grabs Iori by the neck, while shedding a tear, showing that he greatly cares about her. Then, Naguma Sawarabi annihilates all the puppets before they can kill Iori, and attempts to do the same to her.