if you guys noticed the MC originally was a normal person but then Jormungandr(the snake) came and tried to possess the MC and use his body as a vessel for himself although the MC was somehow able to keep himself from being taken over and even gained an ability from the experience(poisonous blood) however every time he used the ability you could tell that him and Jormungandr would merge together more and more ever slightly but I think that medicine he injected him with just sped up the process so instead of them berserking out of control I think this might become a solid stable fusion.
Chapter 12 is the final chapter so don't expect anything, it's been axed with forced ending. The author failed to built hype so it's not popular enough =w=