Mahiru Seki

Mahiru Seki is a former middle school student and a childhood friend of Kou Yamori and Akira Asai. Despite the positive reputation he had a school, Seki was secretly somewhat vain and only enjoyed the company of Yamori and Asai. While working at his family flower shop, Seki met Kiku Hoshimi, a vampire who eventually developed a relationship with him. Seeking to become a vampire himself to evade his everyday life, he started dating Hoshimi, and as time passed, Hoshimi had Seki completely struck with love and abiding to her influence.

Willing to enact Hoshimi's wish to become human and follow her words, Seki discarded all of his close friends and belongings so that his mind could only be locked onto Hoshimi, who in turn also fell in love with him. When the couple was being chased after by Yamori, Nazuna Nanakusa and Kyouko Mejiro, Seki and Hoshimi fled to Hokkaido, where they prepared for Hoshimi's theoretical conversion. However, after a misunderstood quarrel with Yamori, Seki had a meaningful conversation Nanakusa about Yamori and the two friends made amends.

Appearance
Mahiru is a young boy with a darker faint skin tone who usually wears his school uniform consisting of a gray blazer, under which he wears a red hoodie, gray pants, and white tennis shoes. His hair is dark blonde and tied in a little ponytail.

After choosing to become a vampire, he lets his hair down and starts to wear baggy clothes, described by Kou as "looking tired."

Personality
Mahiru is a kind person that tries to keep a good and relaxed atmosphere with the people around him, able to socialize with his classmates and teachers, making him very popular in school.

But that's a facade under which lies a depressed and traumatized person who resents his family for the emotional abuse they put him through. Similar to Kou and Akira, his only genuine friends, socializing with his schoolmates is not fun to him. He is tired of constantly being pressured to spend time with them and feels a catharsis after telling them how he actually feels, despite getting beaten up by them. Mahiru was a timid and quiet child but started copying his brother's personality after he died so he could become popular. Despite not seeing them as real friends, Mahiru felt lonely without the other students.

After spending time with Kiku Hoshimi, Mahiru undergoes a drastic personality change, becoming rude, blunt, violent, and excited about killing humans in the future. However, that that was a byproduct of his coping with the stress of Kiku's looming death. After fighting with Kou, he mellowed. His depression has become much more apparent; his words often have a melancholic undertone, and he isolates himself from everyone except Kiku. Despite being willing to abandon his friends and family, he is still attached to Kou and Akira.

Family

 * Mr. Seki - Father
 * Mrs. Seki - Mother
 * Shougo Seki † - Brother

Allies

 * Kou Yamori - Former Classmate and Friend
 * Akira Asai - Former Classmate and Friend
 * Kiku Hoshimi - Girlfriend and Love Interest
 * Akihito Akiyama
 * Hatsuka Suzushiro
 * Nazuna Nanakusa - Former Enemy and Friend

Enemies

 * Michihisa Kanou †
 * Kyouko Mejiro

Kou Yamori
Kou and Mahiru are childhood friends. He felt like he could be himself around Kou when they were little. Despite that, he kept copying his brother's personality and didn't tell Kou the truth about his family. Mahiru was envious of Kou since he felt lonely without others, while Kou never seemed bothered when he was alone. He also respected him since Kou didn't need to rely on others. They understood each other well, and Mahiru often thought of him after Kou dropped out of school. After a vampire assaulted Akira, Mahiru opposed the idea of Kou becoming one and scolded him. Later, he learned to accept it and offered Kou to drink his blood if he became a vampire. While initially confused by Kou's lack of hesitation, Mahiru soon understood Kou's reason and used it as a motivator to become a vampire himself, even proposing they compete over who gets to become one first.

After Mahiru decided to become Kiku's servant, their relationship drastically changed for the worse. He enjoyed toying with Kou as they talked and kept creeping him out with his radical personality change. He felt upset when Kou took Anko Uguisu's side and suggested that Mahiru was just being used by Kiku, beating him up. When Kou turned into a half-vampire and almost killed him, he felt betrayed because Kou didn't tell him about his powers before and revealed that he was incredibly jealous of him for "being special," ending their friendship on the spot.



He later gives an indirect hint of where he's headed, seemingly inviting Kou, and is shown to still care about him as he values a photograph of himself, Kou, and Akira too much to burn it. It's revealed that Mahiru regrets how he treated Kou and is happy that he came to see him. However, because of a misunderstanding, Mahiru is scared of Kou and thinks he wants revenge, causing him to run away from Kou in fear.

Kiku Hoshimi
They met when Mahiru delivered flowers to Kiku and started meeting from then on. Kiku tells him the words he wants to hear and listens to everything he says, including his worries, making him feel fulfilled and understood and falling in love with her. That led him to stay with her even after she was revealed to be a vampire, despite witnessing a vampire almost kill someone close to him. Thanks to Kiku's manipulation, Mahiru was willing to leave behind everyone he knew and wanted to protect her life and secrecy at all costs. Mahiru was shown to be frustrated because she still hadn't turned him into a vampire, but he said that, while he'd like to become one, he was fine with it not happening as long as he got to stay at Kiku's side.



He is not entirely himself because of Kiku's vampiric charm, which, as he describes, decreases his capability to think and puts him in a state of euphoria. Despite his loyalty, Mahiru is willing to go against her wishes and secretly keeps a photo from his past, even though Kiku wants him to burn his past belongings. He wasn't afraid to confront her when he noticed her keeping secrets, insisting that Kiku talked to him properly.



It is revealed that, on Halloween, Kiku told Mahiru that she would die soon and that she wanted to die as a human with him killing her. He was heavily upset but eventually accepted it, as according to Kiku herself, she would die soon, no matter what. Mahiru knows that Kiku might be lying to him but trusts her because he loves her. He doesn't care that Kiku might trick him, as she is everything to him.

Akira Asai
Like Kou, Mahiru is a close friend of Akira. He wasn't initially close to her, calling her an idiot when they were little children. Still, they eventually became genuine friends, feeling a connection they didn't have with anyone else due to their similarities. She, along with Kou, is one of the most important people in his life. They hung out at school, and Mahiru talked with her about the things going on in his life, like dating someone. After Akira almost got killed by a vampire, his opinion of vampires turned negative for a while, and he didn't want Kou to become one. He consulted Akira about becoming a vampire and shared his worries with her. After joining Kiku, he was still on relatively good terms with her before bidding her farewell. As he burned his past belongings to eliminate his future vampiric weaknesses, he looked at a photo he had taken with Akira and Kou and decided to keep it.

Mrs. Seki
After his brother's death, Mahiru was constantly neglected by his mother, who kept hoping that her older son would return one day. Ever since that happened, Mahiru's room was never changed and still looks like the typical room of an elementary school student. Mahiru wasn't allowed to go on a school trip because "his brother wasn't going." This treatment caused Mahiru's frustrations to build up and eventually turn into silent resentment. He still cared about his mother, helped his parents in the flower shop, and made excuses for his mother's abusive behavior, believing she was broken from the shock.



After Kiku confronted her and explained that she was aware that Shougo was dead but didn't want to accept it, Mahiru reflected on his past and confessed to his mother that he used to hate her to the point of feeling exhausted but that he doesn't feel that way anymore. He explained that he now felt nothing for her and used the opportunity to taunt her with a smile before leaving his family for good.

Abilities
As an average human, Mahiru doesn't possess any extraordinary abilities.

Trivia

 * Mahiru is one of the few characters yet to be featured on any volume cover. Though, he was featured on the cover of the official fan book.
 * Mahiru confessed that he does stare at attractive people's bodies and knows how not to get caught.

Quotes

 * "Farewell, mom. Don't worry, I'm sure, Nii-san will come back. Just stay patient, like you've been until now."
 * "Cleaning up my personal affairs before becoming a vampire is a lot like preparing for suicide, huh..."