Death Lord

Death Lords could be found in Naxxramas. They were found in the company of two Death Knight Cavaliers.

Abilities

 * Aura of Agony — Similar to Deathknight Cavalier but stacks about 10times faster.
 * Frontal Cleave — Melee strike against all enemies in front of them.
 * Death Coil — Fears one opponent and sends them running for 3 seconds. During that time, it drains life from the opponent.

Strategy 1
Tank far away from the raid and focus all ranged on them. Kill them first.

Strategy 2
''Not entirely sure what he did, but we made short work of him. Just had our main warrior, acec, get up in his face, and we killed him before his two rider friends.''
 * Written by Lockdown of WowVault

In his pack with two Deathknight Cavaliers, if you kill him first, then wipe, the Death Lord does not respawn.