At least latest chapters may explain Vampire's origin. I'd guess Vampires come from a Earth-like planet which was attacked by Aliens, and they have come here in order to seek revenge.
Good chapter, it shows what are Aliens capable of. I'm wondering where do the vampires fit here???
For those arguing about invisibility, I can't think of a single use of it that leads to victory, so better Kurono won't use it. Being invisible is useless against Aliens.
