Tsubaki is the main antagonist at the beginning of the story. He is the 8th Servamp who should, originally, not exist - that may be the reason the other Servamps did not know of him at the beginning. He is also called "Who is coming?" Tsubaki is the Servamp of Melancholy. He often laughs for no reason just to find it boring a few seconds later. When he is in animal form, he has the shape of a two-tailed fox. In contrary to the subclass of the other Servamps - his subclass can face the sunlight and are often good fighters.

Tsubaki has a strange sense of humour, often laughing at the simplest thing only to find it boring a few seconds later. He claims to hate humans and his vampire siblings, seeking to start vampire-human war. When it comes about fulfilling his goal, he is merciless and has no hesitation to kill innocent humans because he doesn't like them, simply stating that it's fair.