I'm a level 48 life, (I've been soloing the game so far) and I've been stuck on this quest for a while already. So if anyone wants to help me that would be great!
It's tough to get real-time help on a forum in which posts can take a full day to appear.
For Mr. Grimcaster, I recommend that you buy some 90% Death shields at the Bazaar and put them in your sideboard. Use one whenever you don't have any protecting you.
Now take out his minion first, then blade and trap your Centaur to hit Mr. Grimcaster with the maximum force.
Oh gosh, I hated that quest. Thursday, February 10th 2011, 4:30 Eastern time, the Basilica, Dragonspyre, Pixie Realm. I really don't want you have to deal with what I did to get someone to help. Look for Quinn Dragonwhisper. :-)