Boss of monsters #32 (Nightmare, level 25), dungeon level: 7
Based on monster #99 (Overlord, level 22)

HP: 2000

Damage: 25-45

Magic immune; Fire resistant; Lightning immune (same as base in Horror/Purgatory difficulties)

Color translation: 345678
AI type: 2 (common melee attack), subtype 3
Pack trigger: 1
Pack value: 99
Special sound: 0