>>121396Kou can turn into a half-vampire by hurting himself, mostly with some piercing thingy, and he has all the upsides of being a vampire with none of the downsides. He uses his vampire form to fight a new group of vampires that show up, and most fights end up them phasing through walls and other bullshit.
Thankfully it ends after about 10 chapters or so and there is a school trip arc, but it's pretty meh from that point onwards.