I been thinking about a theory and just want to share it, what if the Mc has been training with the (currently and past) serpents until he left home and lost his memories for some reason ?
We knew his mother was one of the first serpents, he seems to know serpent (sniper with the mask), and maybe they don't want him to know because he could be a similar situation like Gracie, too dangerous to let loose, so what do they do? They send him to Cordia and make a contract so that he can't leave, and keep trying to kill him (that seems stupid or maybe it's another family) so that he can grow on his own, already seen when Eiza tries to kill him. I know it's not to much but it could be a possibility.