When a Destroyer Demon possesses the body of a Knight, it transforms it into a Knight of Hell, its armor blackens, fire licks from the edge of its body and its eyes become burning, fiery orbs.  A nearby horse will also be possessed, becoming a Hell Horse (a maximum Hit Point 5 HD brute).
 AC: 22  HD 10 HP 41
 
 Resistance: 22;  vs. magic 13
 
 Mods: W +3/N+7/S+12
 
 Speed: 30', 65' when mounted on a Hell Horse
 
 Morale: +12
 
 Stealth  0 Perception 0
 
 Attack, Melee:  +12; Damage:  3d8+2 slashing (arming sword)
 
 Attack, Melee:  +12;  Damage: 3d8+2 piercing (lance, double on charge)–Reach
 
 Attack, Melee::  +12;  Damage:  3d4+2 bludgeoning or piercing (mace or dagger)
 
 Terrible Critical: scores a critical hit on 19-20, which also inflicts the pained condition
 
 Riding Master: advantage to all riding checks and can mount/dismount as quick action
 
 Knightly Combat: various advantages when fighting mounted
 
 Hellish Defense: resistant (half damage) to all non-magical weapons, arcane spells, and natural weapons
 
 Immune: fire and cold
 
 Terrifying Aspect: all human NPC's must make a morale check when encounter begins
 
 Hell's Command: the Knight of Hell can give orders to any Imp, Pit Spawn, or Undead of fewer HD than it has.
 
 S+12 D+12, C+7, I+7, W+7,Ch+7