Cerberus

Alpha Tactics. The Cerberus has advantage on an attack roll against a creature if no other creatures aside from the target are within 5 feet of the Cerberus.

Multi heads. the Cerberus has an advantage on wisdom and perception checks and on saving throws against being blinded, charmed, deafened, frightened, stunned, or knocked unconscious.

Wake full. while the Cerberus sleeps, at least one of its heads is awake.

Bite. melee weapon attack: +2 to hit, reach 5 ft one target. Hit: 8 (1d8 + 4) piercing damage plus 7 (2d6) fire damage.

Fire Breath (Recharge 4-6 [2 heads] 3-6 [3 heads]. the Cerberus exhales fire in a 15-foot cone. Each creature in that area must make a DC 12 dexterity saving throw, taking 12 (6d6) fire damage on a failed save, or half as much damage on a successful one.

Multi Attack. The Cerberus makes as many bite attacks as it has heads. if available, it can use its Fire Breath in place of two attacks.