Sei bears the title of dragon king of the east, or "ryuuou," and is often called "ryuu-dono" as an honorific. he also bears the titles: prosecutor of the east and young emissary. he controls the night of hong kong and the special zone, protecting red blood and black blood. he's a direct descendent of a chaotic bloodline. Sei also created the barrior and implemented the restrctions that protects the special zone. his eyes are the " switch" for opening and closing the barrier. when he opens his eyes, the barrier opens, and vice-versa. he can turn into an enormous golden dragon made of pure energy. before the start of the story, Sei's appearance looked that of a person in his low twenties. sometime in the past 10 years, he was reborn as a young child. even though he was reborn into such a cute state (as Jiro puts it), Sei is serious and is one of the most powerul vampires in the story, which makes him highly respected. he could easily make a vampire uneasy with his powerful aura. he also has an older sister called the dark princess of the North.