Churtle

You can use any of the other Geffen Arena cards that boost attack as a replacement, or slot a defensive card in instead since you'll have mobs near you constantly. All skills crit in Niflheim, so you can build crit into everything when you start to finalize a build. You don't need to do this if you're new to the server, but endgame setups basically all use crit setups. Keep in mind however that skills that aren't officially crit skills can still miss even when you are/should be dealing critical damage.

No poison garment for ruins?

Churtle