It was a whole other week for them to reach the outskirts of the Fenrir village. Cain spent those days looking for the best way to mix the high human with the abomination.
The conclusion is that he needs to evolve into a high human first by absorbing a lot of Mana. And just before his evolution to a high human could end, he need to initiate his evolution into an abomination.
This was a dangerous process to take when doing an investigation so Cain started it in the middle of their way toward the Fenrir village.
He started slowly compressing Mana inside his body using the lumps of dead tissue left in his body by Alice's curse. He coupled that with the constant consumption of Mana potions. This had kept pushing his Mana over the limit.
His body had started to naturally adapt and evolve. In the same way, he went from a human to a Mana enchanted human. He was now slowly going to become a high human.