A mysterious enemy.
Viktor lost a lot of blood by studying the blood of the corrupted goblins and comparing it to his blood, and also better understood blood and how to control it.
With his own blood and mana he controlled the blood of the goblins and observed that the two blood types were not compatible without modification.
So he modified them and learned in more detail how to keep the blood in balance in order to use it as a power.
Then, despite feeling weak and tired, he felt how his blood pumped, he felt the balance of "elements" in it, that is to say, its composition. And finally, he felt what his master mentioned…
He felt that he could feel his blood and control it with his mana, felt that he could even increase the pumping of his blood and perhaps create it in other places or at least control it easily as if his blood were another limb.