Bramble Witch
From RoR Wiki
Bramble Witch location 16.2k, 4.5k Chaos Wastes, NW
Pull her through the back of the bramble next to the big vine. When she says my seeds take root you must taunt her or she heals bigtime. When she says the word succumb knock her down or she will AOE and one shot your tank. Heals and ranged stay on the hill to avoid AOE.