A couple of thoughts on his future:
There are plenty of good fighter paragon paths, but I was looking at Bear Warrior the other day, and it’s surprisingly good for fighters. The key is the +1 AC and free second wind while raging. OK, so at level 20, you get one rage (and it’s a good one). But is that worth the multi-class feat and the out of class paragon path?
Well, if I multi-class Collin into barbarian and power swap his level 9 daily for Rage of the Death Spirit, that’s pretty darned good. Then I have two rages per day, which means he’ll be raging most of any given LFR module. He’ll get the amplified damage output I’ve been wanting, without giving up any of his multi-marking ability. And Rage of the Death Spirit is amazing for fighters: as a free action, at the beginning of your turn, you can mark everything within two squares. And you get a +2 to hit marked targets. Plus the two rages and the paragon path encounter power boost Collin’s damage, which has been a slight concern.
But I’m not at all sure I can justify it in roleplay terms. He’s a pretty calm guy, used to be a farmer and all. Is there any shapeshifting/berserkergang tradition in Chessenta that I could make use of?