Lazarus

Archbishop Lazarus, of the Order of Zakarum  from the lands of Kurast, acts as the warden of the Primal evil Mephisto's soulstone.  The once holy order has been twisted and corrupted by Mephisto over the course of 253 years.  Lazarus is sent to the domain of King Leoric to beguile him and free Mephisto's brother Diablo. Lazarus arrives and quickly charms Leoric and his people alike, hiding his true goals masterfully. Eventually Lazarus enters the catacombs beneath the monastery that serves as Leoric's court and confronts the trapped Diablo . The Primal Evil tells Lazarus he requires a body so they set there sights on  Leoric. Diablo, in his weakened state, is unable to fully dominate the man's mind and Leoric begins to act increasingly insane. Lazarus attempts to shield the battle raging within the king's mind from his people but eventually it can no longer be hid. Diablo forsakes Leoric, leaving him twisted and broken, and instead implores Lazarus to return with his son.  Lazarus abducts the king's young son Albrecht and brings him to Diablo to serve as a mortal shell for the lord of terror. By this point the townsfolk are enraged at the loss of there king and prince and Lazarus returns to them and deceives them one final time. Thinking quickly Lazarus rallies the townsfolk into a mob to hunt for the prince, but instead leads them to the lair of the butcher. The butcher , a fearsome demon who empowers Diablo by spilling  the blood of innocents, massacres the townsfolk and Lazarus disappears into the catacombs once again now serving as Diablo's lair. Lazarus now only has to help Diablo regain his full might before he breaks free of his prison and rejoins his brothers, the other two Primal Evils. It's at this point a brave and mighty hero enters the catacombs and slays Lazarus, ensuring that the treacherous archbishop  never deceives another liveing soul again.