Thornheart will not only keep a mob on low health for a great deal of time (a la plague) but also do a lot more damage. Stack it a few times, come back to a mob later, and it'll be gushing or writhing if it's not dead already.
Treants are amazingly healthy and deal a lot of damage. If it's a risky fight, use it like a pocket warrior and heal it.
Bearform dishes out a ton of damage. Use a pet to tank, use bearform to hurt.
Curative and protective herbs are your friends. You won't find offensive/natural as useful exploring.
They can cure a wide range of maledictions, and with herbal regeneration can survive many more since you'll regen about 50-70 hp inbetween ticks with only 1-2 herbs. Exploring during curing moons means you easily out-regen immolation even under fire malison :)
Druids suck at hell. But their decompose does work in limbo, making you a mean ass gear hoarder for the first level.
Yhorian