Large Fiend (Devil), Lawful Evil
Armor Class 18 Initiative +7 (17) Hit Points 228 (24d10 + 96) Speed 40 ft.
Saving Throws Str +5, Dex +7, Con +9, Int +4, Wis +7, Cha +9
Skills Insight +7, Perception +7, Persuasion +9
Damage Immunities Cold, Fire, Poison; Poisoned
Senses Blindsight 120 ft.; Passive Perception 17
Languages Infernal; telepathy 120 ft.
Challenge Rating 14
If the devil dies outside the Nine Hells, its body disappears in sulfurous smoke, and it gains a new body instantly, reviving with all its Hit Points somewhere in the Nine Hells.
The devil has Advantage on saving throws against spells and other magical effects.
The devil makes three Ice Spear attacks. It can replace one attack with a Tail attack.
Melee or Ranged Attack Roll: +10, reach 5 ft. or range 30/120 ft. Hit: 14 (2d8 + 5) Piercing damage plus 10 (3d6) Cold damage. Until the end of its next turn, the target can't take a Bonus Action or Reaction, its Speed decreases by 10 feet, and it can move or take one action on its turn, not both. Hit or Miss: The spear magically returns to the devil's hand immediately after a ranged attack.
Melee Attack Roll: +10, reach 10 ft. Hit: 15 (3d6 + 5) Bludgeoning damage plus 18 (4d8) Cold damage.
The devil casts Wall of Ice (level 8 version), requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 17).