NOT a realistic portrayal of DID
Yuuma, in costume as the park's mascot, and a janitor are working at the same amusement park and meet when saving a boy from getting assaulted at the park. later that day, the janitor is introduced as a new roommate to Yuuma, but the janitor has a certain disorder which makes him a little different from others and he claims that he and Yuuma already know each other very well. he gets upset when Yuuma doesn't remember being close to or meeting him, but Yuuma really can't seem to remember...
Adam no Rokkotsu