Seo Ji-hoo

Seo Ji-hoo is the first son and successor of Seo Gang Min (the vampire leader) and the half-brother of Seo Kang-hoo. His mother died after giving birth. Even so, he is determined to seal his position as the future leader, despite Kang-hoo's assurances that he has no interest taking it from him.He is seen as rude and frequently playing around with women. However, he is actually a proud and arrogant vampire that is confident in his abilities. Much of the flirting throughout the series comes from his desire to find a human bride-turned vampire.

Ji-hoo has long silver hair that goes past his shoulders. It is thick with spikes on the top & flattened straight around the neck and bottom. He has wide eyes and well defined eyebrows.

He met Yoo Da-in in his search for human girl turned vampire. Da-in's gang came to fight Ji-hoo's group but were easily defeated. Thinking Yoo Da In is a girl, he attempts to bite him, only to be interrupted by Kang-hoo. A fight ensues and Ji-hoo stabs his brother. He meets Da-in again at the mansion and at first, he was completely sure that Da-in is a girl. He points out that the only way Kang-hoo could survive his wound was if he drank her blood. The fact that Da-in was still alive afterwards confirmed his beliefs. But when it is confirmed otherwise, Ji-hoo tries to kill him. He has no need of a human man turned vampire. He treats Da-in like a boy afterward until Ji hoo finally drags him to a cellar, rips open his shirt and watches with interest as he turns into Medusa.

Seo Kang-hoo
Kang-hoo is Ji-hoo's half-brother who is also their father's heir. Kang-hoo is kinder than Ji-hoo.

Yoo Da-in
Da-In is the boy who turned into a girl after becoming a vampire. He eventually falls in love with her/him.

Trivia

 * In the English Version, his name is ' Joseph Mason ' (or just 'Joseph ').