What a b***it. From the start of the game - that was the whole Damian's plot. He acted like he doesn't (pretty obvious, because resurrecting means death for Damian since he inverted the Sould Forge spell; this, actually, a lie spread by Damian itself, I believe) because he wanted to make Dragon Knight (protagonist) and Zandalor do the job (the Damian itself wasn't the dragon descendant so he wasn't able to do some things) for him. As we can see in the end-cutscene he is not surprised (not even a little) that Ygrena has awoke, because he waited for it since his plan succeeded. How in the hell these "reviewers" come to such incorrect conclusion - hard to imagine for me.
I'm sorry, did you play the game before you went and started offending people you don't know on the internet? And did you play the same version of the game that we did, in a language you are capable of understanding? The game's dialogue EXPLICITLY STATES that he did not know anything and that he is surprised. In fact, the dialogue IN THE CUTSCENE YOU MENTION explicitly states it. This is not a matter of interpretation or of missing clues that point to the real plot - the text of the game specifically describes what has happened, and Damian's role in these events.