He is a good man, altough he is quite passive.
In Season 2 Episode 3, it is revealed that Mitsuru was seeing another woman named Kono that caused Kie Tsutsui to file for a divorce and she then decided to take Hikari Tsutsui or Kaoru Tsutsui back to her hometown.
However, in Season 2 Episode 4, Kono revealed that she and Mitsuru were just having dinner, but nothing else happened as he turned her down and he later talk things out with Kie at the park.
- The name Mitsuru means "charge" (充).
- Mitsuru's surname Tsutsui means "cylinder" (筒) (tsutsu) and "well, mine shaft, pit" (井) (i).