She helped me to kill the unweakened undermother and survived over 30 runs in SoH
Duell and Heavyhand are very useful, also don't give her too much endurance, otherwise she will use healing not so often. And intervention is very useful if you have enough mana pots, that way she won't die too often.
Ps: she can't be used for ark, you have to do that alone
No, think of this again. Your main source of mana is mana potions, unless you only makes small runs on recovers only. I found I rarely ever use recover with Hirge. And if you dont rely on recover much, larger mana pool is useless. Spending any trait points on personality is a waste.