Aspect of Hatred, Mephisto's Disciple is a unique Morlu Incinerator found in the Silver Spire Level 2 within Act IV of Diablo III.
In Campaign Mode, it first appears as Deckard Cain's ghost, revealing its true self after players talk to it. Killing it is not mandatory.
In combat, it has Electrified and Thunderstorm affixes, and in addition its innate Repulsion ability deals considerable damage.
A bounty may be offered to kill the Aspect of Hatred, in which case the secondary objective is to kill 75 enemies.