Seiji Komori (小森 セイジ Komori Seiji) is the adoptive father of Yui and a friend/acquaintance of the Sakamaki family.
Seiji's current appearance has not been shown. Partial images from the anime and manga show that he wears a cassock.
Not much is said or shown about Seiji except when Yui has a flashback in the prologue of the game of when they both talk about her moving into the Sakamaki house. He seems to care a lot about Yui's life in Japan, as seen in the prologue where he doesn't want Yui being caught up in his work and not being able to attend school. He seems naturally kind but is a little mysterious/secretive as he doesn't tell Yui what his work is for when he flies to half way across the country to Europe.
In Ruki’s route (in MORE,BLOOD), Yui speaks about her past with her father with lots of love. She tells Ruki that her father was very gentle and kind person who made her feel very happy and protected.
It is also unknown whether Seiji ever tries to contact Yui. Seiji seems to be unaware of who actually lives in the Sakamaki household or the fact that it's a house owned by vampires. As suggested by Laito, Seiji purposely left Yui in the Sakamaki household as a part of a deal between the church and the vampires. In Haunted Dark Bridal, it is revealed that the church wanted one of their own members to become the next sacrificial bride, in hopes of dethroning the current vampire king, Karlheinz, and then control the next one that will own the sacrificial bride.
In the MORE BLOOD game and manga, he finds Yui in the church and is relieved that she is safe. He tells her that a friend of his had told him she was in danger, so he rushed back from his overseas work. He is about to reunite with Yui when he suddenly catches a scent coming from her then tells her to stay away from him calling her 'filthy'. He pulls out a gun, points it at Yui, and tells her that the daughter he loves is dead, and all he sees now is a vampire wearing his daughter's dead skin. He tries to kill her,in order to save her soul.
He appears again in the DARK FATE game in Kou's route. Ruki hires Seiji to assassinate Kou for betraying Karlheinz. He chases Kou and Yui, eventually cornering them in a cave. Yui tries to persuade her father to not hurt Kou, but Seiji refuses and he decides to kill her as well, believing she is now a vampire. When Kou tries to interfere, Seiji tells him to stay out of it saying that Yui is his daughter, so he gets to decide how he deals with her. This prompts Kou to question him about his role as a father. Seiji seemingly becomes hesitant but he stays firm with Ruki's orders and procedes to kill them both, only to be stopped by Yuma and Azusa. When Seiji sees the Sakamaki and the Mukami brothers working together to save Yui from Shin, he has a change of heart and helps the two families by shooting Shin. Afterwards, he explains to Yui that he saw the vampires helping her and he now thinks humans and vampires can get along with each other.
After Richter implanted Cordelia's heart into Yui, he handed the baby to Seiji. Seiji raised Yui as his daughter ever since then.
According to Yui he loved chess and taught her the rules when she was young.
Seiji is a priest but he is also a vampire hunter. A young Reiji hired him to hunt and kill Beatrix, by giving him a photograph. Seiji said it would definitely be accomplished and one day he would return to kill him too. Reiji said he was welcome to try and the two were clearly going to have a long relationship.
He is a skilled vampire hunter who is well versed in the use of anti-vampire weapons. Reiji described Seiji as having 'marvelous' ability.
|Sakamaki Brothers||Ayato Sakamaki • Kanato Sakamaki • Laito Sakamaki • Shu Sakamaki • Reiji Sakamaki • Subaru Sakamaki • Kino|
|Mukami Brothers||Ruki Mukami • Kou Mukami • Yuma Mukami • Azusa Mukami|
|Tsukinami Brothers||Carla Tsukinami • Shin Tsukinami|
|Others||Karlheinz • Beatrix • Cordelia • Christa • Richter • Seiji Komori|