https://imgur.com/a/ymTZhsL
All the best builds for Tier 1/2/3 of the first 3 worlds, for wood & iron. Remember card levels have an impact and your best may vary a bit depending on that, but they're gonna be good baselines to work off of for anyone having trouble.
Shiverhorror's definitely the second strongest mage in the game, but any clan can beat him no problem. Bear in mind you can get over level 200 fairly routinely if you're playing well, so you win out just by raw power more than anything. That said, every faction has super strong focuses/combos that you can abuse.