Dark_Lord was an encounter from an earlier version of the Citadel. In since updates and patches Dark_Lord has been removed.
Dark_Lord typically uses one of four moves in encounters: Taunt, Flail, Flame, and Demonic Form
Taunt: Verbal boasts and threats provoke physical attacks from opponents. A Taunted Foe cannot use magical attacks.
Flail: A non-combat move, Flail negates Logic based attacks and prevents flanking maneuvers
Flame: Fire type, low damage. May leave a burn
Demonic Form: Appearance changes, no change to stats
XP and Loot Drops
Low XP granted for defeating Dark_Lords, also before the patches, Dark_Lords had a very high respawn rate so getting away from them was difficult. Items dropped: Thin Skin (junk) Demonic Paraphenalia (x10 can be fused into 1 dram Demonic Essence)