Ghûl cuir (Bat boy)

Cosmo is a pretty chill dude. He goes to school, messes around with his friends, does his after-school activities, etc. Not only is he intelligent and gets good grades, but he is skilled at many things such as Karate, Judo, and other fighting activities (I'm so uncultured that I couldn't find any other names...). He is also pretty cool-looking with his fangs and wolf-cut black hair (IK this is long).
Anyway, he goes camping for the weekend and decides to explore on his own, around the area when he can't sleep one night (yes IK very brave). He stumbles upon an abandoned warehouse and his adventure starts there...