A thirteen year old boy who was once Nanami's neighbor. Because of how often both were left alone they formed a type of brother, sister bond.
Yuzuru: (will contain spoilers)
Don't you look innocent.
As a thirteen year old he does things thirteen year old's do. Accept without his parents. Living in his little world of near isolation from parental figures he met Nanami, she was kind and took care of him when his parents didn't even acknowledge his existence. Because much like he, Nanami didn't have parents who were around, or much less payed attention. The two easily formed a valuable and much needed bond, dispute their three year difference. Yuzuru dubbed her his big sister, and she, dubbed him her little brother.
But when Yuzuru is coming home from school he see's that Nanami's family is moving. Panicked he confronted his busy mother who informed him that the family had no choice, that one of them had been turned into a vampire. And vampires can't leave the Bund. it was a rule, and she was glad for it, telling the devastated boy to forget about her, she was no longer human.
He cried himself to sleep that night
Oh hello Nanami oneecha--cold hands!
only to be roused by the calling of his name, a little noise, when he opened his eyes, there, before him was Nanami, breathless she descended upon the boy in a heated kiss. The boy was surprised, but he didn't fight it. He submitted to Nanami's demanding kiss, only happy to again have his big sister home..
What big teeth you have.
Then it happen, Nanami's kiss suddenly stopped, pulling away from the boy in a mangled snarl of vampire fangs seeking the boy as it's next food supply. The Yuzuru screamed, and like that it was over and she retreated out the window with the boy calling after her. Even then, when his life was in danger by Nanami, all he could think of was her.
Yuzuru headed to the Bund, looking for her, he wanted to save his sister, and to do that, he resolved that he had to do it himself. Because of this little tactic he was nearly killed by a vampire early on in his quest, but he was saved by Vera-tos thankfully just in the nick of time.
Because of Vera-tos saving him he was able to meet Queen Mina, Akira and Yuki, and tell them about his sister who was missing. And they learned that it was Nanami and she was working with their enemy, a leader of a mass of rogue vampires on the mainland. But they didn't know who the leader was...
That night Yuzuru was allowed to stay with the group inside a van while during a steak out on the mainland, and they got a bite.
Mina and Akira charging out after Nanami leaving Yuzuru, Vera-tos and Yuki inside. It was soon found that Nanami's code had been re-written and thier true enemy was revealed. Her name was Hysterica and she was now Nanami's master, as well as the other wandering vampires on the mainland.
When Vera-tos left the van to join at her Queen's side Yuzuru snuck out after her, to seek out Nanami, and with unexpected help from one of the Elite Eight he managed to find her as she gave a tearful confession. She loved Yuzuru, not as a sister, she loved him as a lover would, and wanted him as her own, but she didn't wish to taint him...
She demanded that Mina kill her to save Yuzuru's innocence and to not dirty
him. But Yuzuru heard everything. He tried to go to her but she pulled away, fleeing from him, which was when Hysterica intervined. She smacked him aside like a bug and took off with Nanami in a bang of Vampire suicide bomb explosions.
Yuzuru would have a chat with Vera-tos, on when and how she became a vampire, though he was in disbelief on why she would simply turn herself and become one. Her answer was because she adored Mina's mother, the previous Queen Lucretia. Telling him Vampires lived by their hearts. They can live forever on just one feeling.. just one word.
Happy to have Yuzuru again..
During the final showdown with Hysterica Yuzuru aided in the fight by keeping Nanami distracted from listening to her master. Telling her that he was her's, he was her desire, though a master's will upon their servant is strong, the desire for what Nanami wanted was even stronger. With Nanami distracted by her blinded love for Yuzuru, she didn't see the weapon in his hand. He impaled the girl with a metal stake, to stop her from setting off the bombs with her cellphone..and to keep Hysterica from getting her claws back into her. It was a hard thing for the boy to do, but necessary. He had to stop her from listening to her master, and it was the only way for him to do so.. as painful as it was.
Hysterica managed to escape the fight to find Yuzuru and what she believed to
Night Night Nanami-Oneechan.
be a deceased Nanami in his lap. She was amused, saying that her little 'piggy' would be joined by the boy soon enough. She went to kill Yuzuru but was stopped by Mina now in her true form. The two fought, and Mina focused on protecting Yuzuru and Nanami.. Though Hysterica laughed that she was protecting a human and a dead body, that laughter was quickly silenced when Nanami stabbed her with the very stake she was stabbed with.
It was found that the stake was hollow, filled with a DNA culture made from Mina's own blood. Mina had over-written Hysterica's code and Nanami was free, now under Mina's command. With Vera-tos' help they finished off Hysterica..
Nanami was free and put herself under Mina's full command, to stay and work for the Queen. Because of this, however, she would have to leave Yuzuru, never to see him again because she would never be able to leave the Bund. Yuzuru asked then Vera-tos if she ever regretted becoming a vampire, when Vera-tos told him no, he smiled and ran to Nanami where she changed him into a Vampire and they embraced, now together and not looking back.
In the anime Yuzuru was seen during a little pool outing with Mina, Vera, Nanami, Yuki, Nelly, Nera, and Nero. While int he Manga he helped Akira hide from the Assassins on this tail, he helps where he needs to help with expertise and remarkable stealth.
Yuzuru seems to be a very likable boy with a good head on his shoulders, though he is reckless when it comes to people he cares for that are in trouble. Not one to hang around in the background Yuzuru via Manga seems to be very involved with the goings on in the Bund.