I am gonna suggest 2 builds
The first consums lots of mana but is cheaper to play with saves you lots of potions
St 2 end 3 int 8 agi 5 awa 2 per 4
Skills
Id recommend staff for int bonus mana surge for mana summoner mage armor aracnist earth mastery disintegrader summoner and mage barrier optionally gate saves you from walking all to the max
It can farm any map easily but costs mana pot lots of them youll still have gold earned so dont wary and its not always a must for mana pots btw
Now for this build it your gonna need lots of mana pots and i mean it for this build i recommend wand
St 0 end 4 int 5 ag 5 awa 5 per 5
Skills
Lighting bolt fire ball ice storm disintigerate arcanist
It might look simple and not strong but i dont even need a companion on hard mode because enemies cant reach me they die by alighting and a couple of hits or fireball etc. Lots of ways to kill