So...

I also hope that he'll die as soon as possible

He's not taking over his body, he's taking his power. Or trying to. The thing is, he's his father and the blind witch's mother said that the vessels absorb their parents' souls to awaken into their power. I think that since Noah is a vessek and his son, the ritual won't work like it should and will instead kill Sigmund. Guess we'll see?

This chapter it showed that vessels that have been drained wither away.

Now I’m scared for Noah, I hope nothing bad will happen to him, not that he’s already in a bad situation, but still, and thank you for your explanation.

I wish the same. I wish nothing else will happen to him, it is bad enough to be raped by your father.

That would be cool if this all backfired on that sick bastard...noah can still get his power from his mother some day too if he can get thru this rape trauma and reunite with his wife. I hope he doesn't despair thinking she was burned at the stake.