Tsubaki Asahina (朝日奈 椿, Asahina Tsubaki) is the fifth son of the Asahina family. He works as Seiyu (voice actor) with his identical twin brother, Azusa Asahina. He is also the oldest triplet brother of Azusa Asahina and 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.
Before Ema joined the family, Tsubaki was very immature, teasing most of his brothers and rarely getting personal with anyone but Azusa. However, he also was shown to feel inferior to his twin brother, often feeling that he was the better actor. Ema helped him to feel needed by someone who wasn't his twin, saying that while Azusa was good at some things, Tsubaki had roles all his own that only he could play. She made him realise that he had to stop comparing himself to Azusa, and just be himself, because it was the things that made him different from his twin that made him unique. She encouraged him in his goals and reignited his passion and drive, but also made him see that there were other people in the world, people that might look at him instead of Azusa. These small actions, that showed how much she cared for him and his brothers, are what eventually make him fall in love with her, and cause him to mature drastically.
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 Azusa loves Ema too, he tells him that he won’t let anyone have her, even him. Which he makes clear in episode 6, when he outright tells him so after Azusa gave Ema a blurry picture of himself when he was younger. The action caused Tsubaki to get quietly jealous, and provoked the later conversation; after he makes himself clear, Tsubaki leaves, believing that he had ensured that Azusa would not interfere. Later, when he is forcefully kissing Ema in the livingroom, Tsubaki is shocked when Azusa violently stops him, clearly stating that he was stopping his brother even though he knew how he felt. The action infuriates Tsubaki, who leaves, still fuming.
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 or anything else. After Azusa's hospitalization, Tsubaki begins to rethink his actions, and eventually goes to see his brother. The two tearfully make amends, with both parties accepting the other's feelings for Ema. This rekindles their bond as brothers, but also ignites the flame of rivalry between them. In the end, the two accept each other as brothers and rivals.
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 episode 7, upon seeing the bite mark Fuuto left on Ema's neck, Tsubaki becomes furiously jealous, and demands to know who had left it. He cuts Ema off before she can explain, saying that it hurt him just to look at it. He then goes on to say that, while he admits he had been a little rough, he meant every word he'd said that night when he kissed her. He then cups her face between his hands and demands she answer his advances. He then slowly leans in to kiss her, before Azusa interrupts them.
When Azusa is hospitalized in episode 8, Tsubaki apologizes to Ema for being so forceful with her, saying that he had been desperate about work and even more desperate to make her his. He then admits that he understands, if things had continued, he would've wound up hurting her, and she would never of be able to recover from it. This would've destroyed their relationship completely, along with any hopes Tsubaki had for a future with her. Ema then tries to persuade him to go see Azusa, but to no avail. Finally, Tsubaki embraces Ema and cries on her neck, apologizing and saying that, although he knew he had no right to do so, he couldn't help himself. Ema smiles, and comforts him. Later, he has several nightmares,(Nightmare) one of which involved Ema saying she could not go out with him, causing him to wake up in horror.
After this, Tsubaki's feelings for her continue to grow and intensify; however, he become less aggressive, not wanting ro risk losing control and harming her. Instead, he becomes gentler and more considerate of her feelings. While he is saddened when she refuses to date anyone at the end, he also tells her, along with Azusa, that even so, he is still deeply in love with her. He then resolves to wait, along with the others, willing to do so for as long as he must.
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.
- His name in Japanese means camellia, which can also be said as 'young or immortal'.
- 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 left-handed.
- 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.
- In the novel, he and Azusa are forced to give up on Ema in Ch. 35.
- In the anime, both he and Azusa reaffirm their love for Ema, saying that they will wait for her as long as they must, and that they will never give up on her.
- He is an Otaku.
- 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.