Nekarat the Keywarden of Fright, Seething Chaos, is a Super Unique Terror Demon located in the Gardens of Hope Second Tier (Silver Spire Level 1 prior to Patch 2.2.0) in Diablo III, Act IV. Nekarat is also a keywarden. He has a chance to drop an Infernal Machine. At levels 61-70, he has a chance to drop the Infernal Machine of Evil, and a small chance to drop any other level 70 device.
He is a greatly empowered variant of a Terror Demon, but does not hide in shadows. Instead he has Jailer and Knockback affixes, as well as radial flame attack that blasts everything within roughly 20 yards of him for high Fire damage. Be wary that this blast hits further than its visual radius indicates. He can also rush forward with great speed, dealing damage and knocking back players in his path.
Because of his greatly increased damage output, it is advised to kite him around the cleared territory, for Nekarat cannot attack from afar. There are many pillars, stairs and impassable circular pits in the area for that purpose.