Troll kings are pretty weak; they don't compare to uniques. With unlimited gems they can replicate exponentially, though
You ought to check out the old Supercombattant tournament thread:
http://www.shrapnelcommunity.com/thr...fpart=all&vc=1
You can also download the game to see the results - they're worth watching.
Most people entered 10-death-gem Tartarian Titans
Elemental royalty are extremely powerful, but very risky in big games because you don't know who already has them, and you can't risk wasting 50+ gems. Most people go with Air Queens, I think, since they start with ethereality and lightning immunity and so forth. I prefer Earth and Fire, but then again, I prefer Ice Devils anyway - much cheaper and lower path requirements. Royalty lack foot slots, too.