Basically just lower mana with various items, then keep a mana flask going throughout the map. Using Sap + Battle Within to generate a few hundred stacks really fast, then deactivate Battle Within to have a slow sustain of up to 350 mana burn.
https://pobb.in/fXrUW6agaB5K
Life
3756
Mana
12
Energy Shield
50
DPS
46K
Effective Hit Pool
87.84K
Chaos Res
-25
Fire Res
67
Cold Res
60
Lightning Res
72
Armour
15K
Evasion
14K
Block
undefined | undefined
Crit Chance
38%
Crit Multi
236%
Rage
0
Strength
188
Intelligence
141
Dexterity
182
Ward
0
Item Quantity
0%
Item Rarity
4%
Movement Speed
32%