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|Physical and Vital Statistics|
|Height||180 cm (5'11")|
|Weight||64 kg (141 lb)|
|Occupation||3rd year High School Student|
|Relatives|| Kou (adoptive brother)|
Yuma (adoptive brother)
Azusa (adoptive brother)
|Game||Diabolik Lovers MORE,BLOOD|
|Manga||Diabolik Lovers MORE,BLOOD Anthology|
|Anime||Diabolik Lovers OVA|
Ruki Mukami (無神 ルキ Mukami Ruki) is the oldest son of the Mukami household. He is known as the 'Brains' of the Mukami family.
Ruki is a handsome young man with short ruffled hair colored with black on top and white on the tips. He has blue-grey eyes and also three black piercings on his right ear. Ruki has two big scars on his back from when he was a child. He wears black web chokers on his neck. He is sometimes seen carrying a book.
He usually wears a grey jacket with a long sleeve black shirt underneath and wears it with black pants and a brown belt. He sometimes wears a long sleeved maroon shirt with a black butterfly print on the bottom left side and wears it with black pants and a black belt. He wears the black web chokers with both outfits.
His school uniform consists of the black school jacket with a white dress shirt that is slightly unbuttoned revealing a long sleeved maroon shirt underneath and a long black tie over it. He wears it with the black plaid uniform pants and brown shoes.
He always has an intimidating smirk on his face matched with a calm tone, but a sense of brutality can be felt in his spoken words. Without dirtying his own hands, he interacts with others as a cruel-hearted military do-S (extreme sadist). Ayato notes that he is an "intellectual" person.
Before he was turned into a vampire, Ruki was a human born into a rich family. He was a spoiled little boy who was a member of the 'aristocracy' and found amusement in treating other people harshly and rudely. However, as karma would have it, Ruki’s father, a kind and generous person, wasn’t good at managing his business/money and became bankrupt.
Ruki found out about his father's bankruptcy when he woke up to the servants ransacking the house for valuables. When he tried to stop them, they banded together to beat Ruki up for all the cruel things he did to them while telling him about the state of his family. To make matters worse, they told him that his mother ran off with her secret lover, leaving only a letter saying that she loves him. After the beating, Ruki went to the garden and found that his father had committed suicide.
Ruki stayed behind in his family home for some time, hoping that his mother would come back (he even wondered to himself how his mother could say she loves him but leave him behind) before he gave up and had to live on the streets, mocked by another aristocrat. He ended up in a orphanage where he was treated poorly by both the other kids and caretaker because he was a former aristocrat with a bad attitude.
The only kids who were decent to him were Azusa, Kou and Yuma, and eventually the four of them devised a plan to escape their ‘hell.' Unfortunately, while the plan started off well, they were pursued and caught. As punishment for trying to run away, Ruki was branded on his back like ‘livestock/cattle.’ As Ruki believed he was at the deepest pits of hopeless rage and despair at the world, Karlheinz appeared and offered the four children the chance to become vampires in order to take revenge on the world that, in his words, deprived them of everything.
Ruki, Yuma, Kou, and Azusa became vampires, and Karlheinz chose Ruki to be the ‘brains’ of the group, making sure that he was well-educated and capable of leading his ‘brothers.’ When he asked why Karlheinz chose to give him all this education when the others didn’t have that, Karlheinz told him that it was Ruki’s new role and that they’re all necessary for his plan. The plan details a human girl "Eve" with the heart of the demon lord’s daughter. "Eve’s" blood would choose an “Adam” who would be able to obtain the power to control the world, and their descendants would change the world. Ruki really felt indebted to Karlheinz, so he worked for him, doing what was needed to help him complete that plan.
Ruki is the eldest son of the Mukami household. Granted by Karl, his job is to be the leader and look after his younger brothers: Kou, Yuma, and Azusa. Unlike the Sakamaki brothers, they have a closer relationship with one another and care for each other. Ruki only really cared for his father, even though he wasn't around much when Ruki was a child. As for his mother, he wanted to believe that she loved him. However, when she left Ruki's father and ran away with another man, Ruki questioned her feelings for him. When his family went bankrupt, the servants beat him up and hinted at what had happened to his father. Upon going outside, Ruki saw his father's corpse hung from a tree with crows feasting on it. He has recurring nightmares from that experience and becomes physically ill when reminded of his past.
Ruki is very strict with Yui. Right off the bat, he forces her to sleep in his room so that he can monitor her at all times, thus giving her limited rights. He also forbids her to go to school since the Sakamaki brothers go there, but he eventually allows Yui to attend school normally. However, even at school, he still monitors her by making her attend his lessons, much to her embarrassment since he is a third-year student. When Yui gets attacked by Ayato at school, she tries to keep quiet about it, but Ruki sees right through her and ends up biting her in the stomach as punishment. At one point, Yui brings home a stray kitten, but Ruki kills it which upsets her and not being able to stand seeing Yui upset, he hugs her from behind to cheer her up. One night, Ruki has a nightmare of his past and when Yui tries to comfort him, he loses control of himself and almost strangles her, but when he regains his senses, he kicks Yui out of his room to ensure her safety. When Ruki and his brothers finds out that Ayato has discovered their whereabouts, he locks Yui in the dungeon to protect her. After some time and with begging, he allows Yui to go out of the dungeon for a bit, but she's only allowed to be in his room. His time with Yui is short-lived when Ayato flies in out of nowhere and punches Ruki, knocking him out. Ayato grabs Yui and takes her out to the balcony, but Ruki manages to regain his consciousness, crawls to the balcony and he grabs Yui's hand, in an attempt to prevent her from being taken away. It is hinted that Ruki actually does care for Yui when he asks Ayato if he is taking her away because he loves her. Ayato laughs and says that Yui's blood is only delicious, then burns the Mukami mansion down, while taking Yui with him. Yui then resides in the Sakamaki house, only thinking about Ruki. After some time passes, Ruki appears before Yui in the garden and he tells her about his past in better detail than before, as well as the "Adam & Eve" plan. He then wishes her farewell since he has finally realised that he can't become "Adam" and she should choose one of the Sakamaki's instead, because she's deserving to be "Eve". By then, Yui has realised that she has fallen in love with Ruki.
He is the main antagonist in Ayato's route and he appears more friendly, gentlemanly and caring towards Yui unlike his own route. When Yui passed out after Ayato forcibly sucked too much of her blood, he helped her to the infirmary causing Ayato to get irritated to find him with her. On one occasion, he tries to convince Yui to leave Ayato and to come with him instead, but she tells him she can't trust him, prompting Ruki to attack her and suck her blood by force. When Yui runs out of the Sakamaki mansion after being provoked by Ayato, Ruki meets her the in forest along with his brothers and they take her back to their mansion. After Yui finally realised her feelings for Ayato, she visits Ruki in his mansion to turn him down and he reveals to her that he was not being serious at all, it was only an act. However, in Ayato's Brute End, Ruki finds Yui wandering through the city streets upset about the fact that Ayato won't touch her or drink her blood. He approaches Yui and tells her that it seems as though she has become accustomed to having her blood sucked multiple times. He asks her if she would like him to replace Ayato, though he considers it provoking to be a substitute. He sucks Yui's blood until Ayato discovers them (having had been told by Laito) and Ruki gets killed, followed by Yui.
Ruki respects Karl Heinz since he is the one who gave them a second chance at life, along with his brothers, thus saving him from the orphanage, or as he dubs it, "Hell". He feels indebted to Karlheinz, so he agrees to work with him for the "Adam and Eve" plan. However, in Ruki's vampire ending, he doesn't mind betraying Karl in order to be with Yui. He claims that he's the "snake who tempts Eve", but she agrees to be with him despite what he believes.
- He is right-handed.
- His foot size is 27.5 cm.
- The book he always reads is a memento from his father.
- His recent interest is making original dishes or recipes.
- He hates strong-flavoured food and drinks.
- He is skilled at cooking and even knows how to flambé.
- He knows how to ride a horse.
- He is fluent in Nordic and proficient in English.
- He enjoys playing darts.
- In the Dark Fate Brute End, Ruki and Yui have a son named Adam. Later, Adam appears to be a first blood and Shin Tsukinami's son.
|Sakamaki Brothers||Shu Sakamaki • Reiji Sakamaki • Laito Sakamaki • Kanato Sakamaki • Ayato Sakamaki • Subaru Sakamaki|
|Mukami Brothers||Ruki Mukami • Kou Mukami • Yuma Mukami • Azusa Mukami|
|Tsukinami Brothers||Carla Tsukinami • Shin Tsukinami|
|Others||Karlheinz • Beatrix • Cordelia • Christa • Richter • Seiji Komori|