ok i am gonna explain all this confusion damn the author really made a mess, Desuraba is first the prequel the story is about the kajus males that transforms into monsters, why it happens who knows but the mc and the few males that were virgin and survived are punt on an island, and are used as experiments for a cure, in there the MC meets his childhood friend then a lot happens and they are freed from the experiment but as a form of punishment the girl of the MC is taken as a prisoner and then this starts I haven't started to read it because I was confused but thankfully I read the first... so hope this explains a little