I had a stone/stone tank for years. He can tank like 3 Giant Monsters but starts loosing HP after that. I can easily tank the two bosses in Croatia but you will die from psi bosses eventually. It's not just the resist/def cap you have to hit. You also must hit the regeneration cap with your roots and you absolutely must work on at least some psi resist. Even so it is possible to be drained to death, though not as easily as most tanks, or killed by psi damage. Furthermore you are not fear resist and something with fear will keep you cowering. The worst thing is you move so slow you just about have to add a slot to swift to move at all other than teleporting, which is annoying. I also wish I chose something other than stone offence, ss would be cooler, mace, axe is ok and giant weapons sounds cool if you can get it. Stone defence is the strongest though and I have taken on several groups when my party wiped and won, which included some psi in them. Just go for psi first.