Mitsuru has mid-length unkempt hair and wears hospital garb.
Mitsuru was in Yu Kitakata's homeroom while he was a student at Kurokawa Academy. He was frequently bullied by his classmate Shinya Kawai, who had assistance from most of the other students in his homeroom, including Yui Suzuki and Yasushi Akaike. Kitakata only issued a light warning when he was told of the bullying, but set up a camera to record what his homeroom was doing after school on September 17, 2008. The camera caught Mitsuru's classmates physically assaulting him and threatening to strip up, then leaving him when he urinated himself. Kitakata was prompted to act too late, as Mitsuru jumped off the roof only hours later.
Mitsuru became comatose as a result of his suicide attempt, and he was visited in his hospital daily by his mother and occasionally by his classmate Yoko Sawa. Kitakata started a secret murder conspiracy to kill any bullies he could out of guilt, with one of his victims being Mitsuru's own bully, Kawai. Mitsuru was eventually moved to Touto University Hospital.
Lost Judgment: 2021-2022
Mitsuru wakes up after 13 years in December 2021, which causes his mother to reconsider turning herself in for killing Kawai. She chooses to betray Kitakata and hide any evidence of Kawai as to prevent her son from being labelled the child of a murderer. During rehabilitation, he is eventually able to take steps.
In January 2022, Reiko sees her victim's body and chooses to atone for her sin. She calls Mitsuru and tells him over the phone that she may not return for a while, to which he replies he knew something was troubling her and he will wait as long as he will need to.