Barrier. The demonic beast is resistant to damage while its barrier is active. Each time the demonic beast takes damage, roll a d6. On a 6, the barrier is deactivated until the end of its next turn and the demonic beast is stunned until the start of its next turn.

Vital Defense. While the demonic beast's barrier is active, critical hits do not inflict additional damage to it.

Renewal. The demonic beast regains 10 hit points at the start of its turn.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., 1 target. Hit: 15 (3d6 + 5) [piercing] damage. 

Flame Breath (Recharge 5-6). The demonic beast exhales fire in a 40-foot cone. Each creature in that area must make a DC 15 Dexterity saving throw, taking 28 (8d6) fire damage on a failed save, or half as much damage on a successful one.

Seal Strength (Recharge 6). Each creature within 10 feet of the demonic beast must make a DC 15 Constitution saving throw. A creature that fails this save deals only half damage with weapon attacks that use Strength for 1 minute. An affected creature can repeat the save at the end of each of its turns, ending the effect on a success.