I wasn't at the show, but I'd say he fits Therion very well.
Very good for the first performance from what I can see by watching the videos (thanks for those btw), I know he'll get even better over time.
One thing I've noticed watching these videos is that with the newer additions to the band, Therion is alot more lively onstage as a result in terms of fan interaction and stuff. That is truly fun and cool to watch. Watching the Wacken video for To Megatherion I did wonder about the various miscues and timing issues that occured in the song, caused in part probably by the looser attitude and vibe onstage. While I dont expect stage performances to be note for note perfect (god forbid, I want rock n rollers not studio musicians lol) I was surprised by how the various soloing interludes in the song were stopped/altered a bit. I think on a Wacken to Wacken comparison, regarding this 2007 performance of To Megatherion to the 2001 performance of the same song, I actually prefered the 2001 version.
I can't exactly explain why, b/c I really enjoy the current line up, but the 2001 version was so much tighter, crisper, and the power and emotion of the song were delivered with alot of gravity, Christopher and Kristian were just on fire during that whole performance (mind you I'm only judging from viewing it on the dvd) and that set's versions of Wine of Aluqah and To MegaTherion really do ecliipse the studio versions of those songs.
Anyway, not passing judgements on the current lineup, in fact, I enjoy the change and fresh prespectives, but just had to put out here my honest opinion about the 2007 Wacken To Megatherion performance. BTW, Lemuria live was great