Revenge our deaths
What They Say:
After the world was infected by a mysterious virus, a pair of orphans named Mikael and Yuichiro find themselves being enslaved by vampires. One day they try to escape alongside the other orphans and all end up being slaughtered by vampires leaving only Yuichiro to escape. Upon reaching the outside world, he joins a group dedicated to defeating the vampires and swears to one day have his revenge.