Alpha Hell Hound (Alerted)

Keen Hearing and Smell. The hound has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Pack Tactics. The hound has advantage on an attack roll against a creature if at least one of the hound's allies is within 5 feet of the creature and the ally isn't incapacitated.

Blindsense. If the Alpha Hell Hound is able to hear or smell, it is aware of the location of any hidden or invisible creature within 10 foot radius.

Pack Leader. If the Alpha Hell Hound targets an enemy, all Hell Hounds in a 15 foot radius are then compelled to attack the Alpha Hell Hound's target. If a Hell Hound in this radius is currently engaged in combat, they do not respond to the Pack Leader. If a Hell Hound is attacked in that 15 foot radius, as a reaction, the Alpha Hell Hound can use up to half its movement to move to the engaged Hell Hound's target.

Alerted. This monster has perceived a threat and has prepared for attack. The effect, reactions, or traits marked (Alerted) may only be used if a threat is perceived before an attack occurs. Otherwise, this monster becomes Alerted after the 1st attack in either a surprise round or 1st round of combat.

Bone Spikes. The Alpha Hellhound has prepared its defenses against a perceived threat and condenses its fur to form bony spines covering the length of its body. AC increases by +3. (Alerted) normal AC is 15 when not Alerted.

Multiattack. The Alpha Hell Hound makes two melee attacks or one melee attack and one breath attack

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 5) piercing damage plus 7 (2d6) fire damage.

Fire Breath (Recharge 5–6). The hound exhales fire in a 15-foot cone. Each creature in that area must make a DC 12 Dexterity saving throw, taking 21 (6d6) fire damage on a failed save, or half as much damage on a successful one. Cannot be done 2 turns in a row

Superior Invisibility. The Hellhound magically turns Invisible until its concentration ends (as if concentrating on a spell), or 4 rounds of combat have passed. If the Hellhound uses Fire Breath, Superior Invisibility is dropped. Can only be used once a day. (Alerted)

Spellcasting. The Alpha Hellhound (Alerted)can cast 1st level: Armor of Agathys. Damage for the spell is piercing and magical. Can be recast when all temp hit points have been expended. Casting time for the spell is 1 Bonus Action or 1 reaction.(Alerted)