Monster Manual, page 132
Two Heads. The ettin has advantage on Wisdom (Perception) checks and on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious. Wakeful. When one of the ettin's heads is asleep, its other head is awake.
Multiattack. The ettin makes two attacks: one with its battleaxe and one with its morningstar. Battleaxe. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage. Morningstar. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) piercing damage.
Hill, Mountain, Underdark