Ziyoteru is the dark side and the 'evil brother' of Kiyoteru Hiyama. He is a science teacher who focuses mostly on spacial theory. When asked to describe himself, he simply says, "Science teacher by light, rockstar by night."
Ziyoteru (usually called Ziyo) differs from his lighter brother in appearance by three things; his hair, eyes, and tie. His eyes are crimson instead of black, and his hair is black but not brown. His tie is reddish-violet and not blue. His outfit is otherwise the same.
Ziyo is kuudere, meaning he is calm and collected, only showing his sweet side to very special people. He is known to have a lot of patience for his students, as they are known to disrupt his lessons. His patience is very limited around his light side, however. They often get into fights and although Ziyo refuses to show it, he has several scars because of it.
He is also often perverted and enjoys watching yuri late at night. He adores to procrastinate on marking assignments and tests.
He is known to have a very sad past. If one stays around long enough to hear the full story, one will end up being tramautized, and for a very good reason.
First, he was created as a prototype. When the scientists were certain that they had everything correct, they left him to the streets, with no further use of him. One scientist, however, had enjoyed creating him and helped him a little bit in the early parts, by giving him some food and telling tales of his creation. Eventually, she was found out and was fired. She stopped visiting Ziyo and he figured that he wasn't needed and so, he left for the other side of Tokyo to start a new life.
After a decade of wandering, he found his brother Kiyoteru, who took him in. Not long after, the one friend Ziyo had made was murdered by YOHIOloid, dying in Ziyo's arms as he tried to protect his friend. Ziyo and his brother lived together for roughly three years, before they were sent to a master in America. This master is unknown, but one knows that he was very abusive towards Ziyoteru and spoiled Kiyo rotten. He is known that he had beaten Ziyo more than once, however. He had favoured Kiyoteru, who had bathed in it and had emotionally tormented his older, darker brother. After two years of this, the police came calling for Ziyo, who was apparently responsible for the death of his best friend. He was kicked out and they chased him down to a church where he called sanctuary, bloody and miserable.
He was called for a trial and lost, to spend two years in jail. During this time, his hatred for the world grew to an amount that it created another soul in his body, Ziyoteru Tsukine. Ziyo's own soul now had to share a body with Tsukine's, creating a twin soul. Once he was free, he ran west, across the continent to find a short, sweet girl who would become his master and finally, not abuse him. He remains there to this day.
None so far, probably half an octave lower.
Ziyo so far does not have any songs, MMD media/models, or original fanart. He so far only has colourovers.
Ziyo struggles to control Tsukine, who simply sits in the back of his mind like a small inner voice. When angered, Tsukine will take control of Ziyo's body, even though Ziyo is the dominant soul. Unlike Ziyo, Tsukine does not recognize positive feelings easily and strives for hate and displeasure, to only stop when Ziyo's life is on the line.
Ziyo also struggles with schizophrenia, OCD, ADHD and psychotic disorder. He takes medicine for these disabilities but sometimes the medicine fails him and he goes into a yandere, unresponsive form who is concerned only about the death of everyone around him. The only way to control him is for positive feelings to be forced upon him. This is mostly done by his girlfriend Kisshu forcing him to kiss her until he calms down.
Kuro is one of his students, possibly his favourite, who he found not only is schizophrenic like him, but has also a very similar backstory. For this, they get along well and Kuro comes to Ziyo for advice on a lot of things.
Tsukine is Ziyo's darker side. They don't get along too well, Tsukine saying everything Ziyo believes but won't say.
YOHIOloid is known to be Ziyo's archnemesis. Having killed Ziyo's nameless best friend then bullying him for the few years they had contact, it is not surprising.
Kisshu is Ziyo's girlfriend. Although he won't say it, he plans on marrying her the moment they both come of age.
None of importance.
Although he is kuudere, when he shows his sweet side he can become very yandere extremely quickly. The only people who are capable of calming him down are his master, who simply talks to him in some sort of lullaby, and his girlfriend, who kisses him until he calms down.
Ziyo enjoys spending time with his master, as he is grateful to her for not only taking him in but not abusing him.
https://archive.is/20130626141952/www.facebook.com/JapaneseBillNye That is his Facebook page, which is admined by LocketShoru and also features Tsukine.