It's The Apocalypse and Turns Out I'm A Vampire

Also known as Vamp Apocalypse Hey there! My first time writing this kind of novel and I don't really know how to write a synopsis for it, so please support it! Kwon Sung-ho is a 17 year old teen who is heralded as the Dark King in his high school. One day, on the way to school he meets a girl who is about to commit suicide. He convinces her against it, but while she ran away she dropped a pocket watch which he picked up. Afterwards he goes to school, where he gets detention. While in detention, he falls asleep and when he wakes up, he sees a screen in front of him telling him that its the apocalypse. Later on, he is killed by a swarm of monsters, but then he wakes up with a screen telling him [Geno Tree Activation Successful]