|Birthday||April 24, 1979|
|Age||31 (Season 1)|
34 (Season 2)
|Relatives||Hinata Rintarou (Stepfather)|
Asahina Miwa (Mother)
|Anime Debut||Episode 1|
|Game||Brothers Conflict: Passion Pink (Playable)|
|Japanese Voice||Kazuyuki Okitsu|
|English Voice||J. Michael Tatum|
Masaomi Asahina (朝日奈 雅臣, Asahina Masaomi) is the eldest of the Asahina brothers and works as a pediatrician. He is very kind and good with kids and cares a lot about his family.
Masaomi has brown hair and brown eyes. He wears a white lab coat with a light brown shirt underneath and brown pants and shoes. He has a stethoscope on his neck with a pink ribbon.
Masaomi has a children-loving and gentle personality. He is rather laid-back and spends most of his free time relaxing at home. He loves his family a lot. He's the typical father figure of the household (considering his age) and looks over Wataru more often than most of the other brothers. He is much more immature in comparison to other characters such as Natsume or Ukyo, however he's still a doctor all the same.
While he tries to be the father of the household, he also had to deal with his own share of emotional problems. Such as his growing affection for Ema that he tries so hard to hide. Before her entrance into the family, he was shown to have something of an inferiority complex, not seeing himself as very important beyond his medical knowledge. Ema helped him to understand that he is the one who protects the family, and that everyone looks to him to keep things calm and keep them all safe.
Masaomi said once that Ema, along with Wataru, is the apple of his eye. He acts as a father figure to her while Rintarou is away, and takes care of her when she's sick or injured. However, like his brothers he has feelings for her, and even says at the end of episode 9 that being like a father to her is a problem for him. He loves Ema and doesn't want her to get hurt. He also gets embarrassed in the Christmas special whenever she talks about how important he is, and excuses himself.
Masaomi cares for Ukyo like an ordinary brother but doesn't seem to have a close connection, which makes their bonding fail. The two of them have the task of keeping the household 'alive.'
Ever since their father passed away, Masaomi has been taking care of Wataru and becomes the father figure of his life. He mentioned that Ema and Wataru are both the apple of his eyes.
- Even though he's a doctor, he can't stand the sight of blood.
- He was the second brother to know that Hikaru dresses as a woman.
- After the marriage, Miwa-san preferred Masaomi to have Ema as his future bride.
- He and Ema gets married in the game in Masaomi's route and later they are expecting a child.
- In the anime, he doesn't give up on Ema, and is still part of the "Brothers Conflict."
- For 2014 April Fool's, on the Brothers Conflict Sylph Dengeki web page, the female Masaomi was named Masami (雅美).
- His Zodiac sign is Taurus, the Bull.