What ever said that Ygerna was awakening Damians powers so that she could awaken the demon? All that was ever said in D2 was that she was just trying to awaken his powers because of what he is, not to awaken the demon.
If you didnt know that there was a demon inside of you but there was somebody who said they can make you more powerful, would you say, "lets go for it" or "forget that. I like being normal"?
