|Birthday||December 31, 1986|
|Age||24 (Season 1)
27 (Season 2)
|Hair||White (brown in high school)|
|Relatives||Hinata Rintarou (Stepfather)
Asahina Miwa (Mother)
|Anime Debut||Episode 1|
|Game||Brothers Conflict: Passion Pink (Playable)
Brothers Conflict: Brilliant Blue (Triplets ending)
|Japanese Voice||Kenichi Suzumura|
Tsubaki Asahina (朝日奈 椿, Asahina Tsubaki) is the fifth son of the Asahina family. He works as a seiyuu (voice actor) with his identical twin brother, Azusa Asahina. He is also the older triplet to Natsume Asahina.
Tsubaki has violet eyes and messy white hair that covers the right side of his face. He has a beauty mark under his left eye. His facial features are similar to Azusa's since they are identical twins. He wears a pair of earrings and is usually seen wearing a pink diamond cardigan under a black blazer, along with trousers, his boots and a pendant necklace around his neck.
In Season 2 he starts wearing a white t-shirt with a pink design along with a pink cardigan (that has alternating gray and pink buttons) and over that a gray blazer with white trim. He also has on black trousers with key chains dangling from his pocket, pink socks, black shoes with pink trim and checked insides, and also a necklace.
Tsubaki is usually playful and easygoing, but can be very pushy sometimes. He likes to tease his brothers and Ema. He loves little sister characters with a passion, so Ema is a dream come true for him. However, he also has a serious side as well, especially when it comes to work. He takes his job very seriously, and he always does the best he can. He’s also an otaku who loves anime, manga, and games.
Once he realizes that he's fallen in love with Ema as a man he becomes increaingly aggressive in his advances towards her. Shown in episode 6, whenever he pushes her down and pins her on the couch before forcefully kissing her. He is also shown to get extremely jealous whenever he sees Ema with one of his other brothers, especially Azusa. However, he later comes to realize that he has to be more considerate of her feelings so as not to hurt her. This causes him to become less forceful with her, but also makes his feelings intensify.
Being his identical triplet brother, he holds Azusa in high regards and expects the best from him. When Azusa was chosen to voice the lead role in an upcoming anime, he told him he would not be happy if he turned it down, and how he wanted to hear the role in his voice and no one else's. They have a very close relationship; in episode six of the anime, Natsume, their fraternal triplet brother, says that it’s not like him to listen to anyone other than Tsubaki, implying that they usually value each other's opinions over everyone else's. After Tsubaki realizes that he loves Ema too, he tells him that he won’t let anyone have her, even him.
This puts a strain on their relationship for a while, with Tsubaki becoming furious that Azusa would stop him from kissing Ema after he told him that wouldn't give her up. He begins acting cold, refusing to listen to Azusa when he tries to tell him to stop being so forceful with her. It even escalates to the point where Tsubaki tells him that he doesn't want to hear anything he has to say about Ema.
Tsubaki enjoys teasing Ema, as shown in episode one when she overhears him and Azusa reading a script and she takes it the wrong way. He continues to lead her on into thinking that he and Azusa have a more than brotherly love for each other until laughing and saying that he got a great reaction out of her and Subaru, who was with them.
After Azusa got the lead role in an anime that Tsubaki had wanted in episode four, Ema consoles him. He said that he was disappointed, but knows that they made the right choice because Azusa is the better actor. Tsubaki then says that he heard her telling Azusa that she likes his voice, and then asks if she likes his voice too. She replies that she does, and that she doesn’t know much about acting, but she doesn’t think it’s about who’s better than who, and that she wants him to stay true to himself, because there are roles that only he is meant to play. When she tries to apologize for saying what she did, Tsubaki kisses her, then says that the best way to get a depressed boy back on his feet is a kiss from a cute girl, before kissing her again.
After that, Tsubaki seems to like her, and he tells her so in episode six of the anime. At first, he says that he’s sorry for kissing her, but it turns out that it’s just part of the script he was holding. He hugs her and says that he won’t apologize, because him kissing her wasn’t just a spur of the moment thing or a whim, and that he’s serious. He then proves it to her by kissing her. When she pulls away in shock, he advances and pins her down on the couch before telling her that he loves her, saying he won’t let someone else have her. He then forcefully kisses her, and Ema almost loses her strength to fight when Tsubaki is pulled off of her by a jealous Azusa. The two brothers confront each other before Azusa tells Tsubaki to leave. Tsubaki glares at him before obliging. However, when Ema calls to him as he reaches the stairs his fist tightens furiously around his script. He then looks at her with conflicted eyes before saying goodnight.
In the Valentine's Day special he has a fantasy about being alone with Ema and being tied to her with a red ribbon. The fantasy ends before he can kiss her though. In the special 12.5 episode, when he imagines his perfect wish he sees himself as with Ema on the beach as her boyfriend. In it, he embraces and kisses her.
The two brothers do not have a good relationship, due to the fact that Fuuto treats Tsubaki like a younger brother instead of the other way around. Tsubaki was shown making snide comments about Fuuto when he was on TV. Also, in episode 7, Fuuto gets under his skin about being able to do any role he is given; Tsubaki later becomes furious when he sees the bite mark Fuuto left on Ema's neck.
- He is the fifth son of the Asahina Family.
- He is one of the triplets with Azusa and Natsume.
- The triplets each have a beauty mark on their faces his is directly under his left eye.
- Tsubaki and Azusa are identical.
- He is the the second brother to kiss Ema, although he is the first to do so intentionally.
- Just like Natsume, in his high school days, Tsubaki's hair was brown.
- Tsubaki is named after the flower Camellia.
- He kissed Ema twice: the first time while he was depressed, and the second time by force.
- He is very forceful and aggressive when it comes to Ema.
- He and Azusa officially give up on Ema in ch. 35.
- He is an Otaku.
- For 2014 April Fool's, on the Brothers Conflict Sylph Dengeki web page, the female Tsubaki's name is spelled as 椿姫.
- He shares the same star sign with Azusa and Natsume; Capricorn, the Goat.