This chump also casts a 20k AE called Autumn Winds. Wasn't expecting that, but /shrug he still keeled over easily enough, especially after dispelling his defensive proc as per the tip below, great catch.
he spawns in nw forest to the left of tunnel both the bitter treants to the left are his PH, partially slowable and the sticky sap is actually a defensive proc so if you cast dispel magic a few times itll get canceled and hell be A LOT easier, so slow and dispel him before attacking :P took 2 or 3 casts of cancel magic to get it off but it worked, killed with an 88 sk 88 bst 85 rng 2 88 t5 clr mercs and a 85 t5 rog merc