Asylum Demon

Demons Sight:  Magical darkness doesn't impede the Asylum Demon's Darkvision.

Magic Resistance: The Asylum Demon has advantage on saving throws against spells and other magical effects.

Steadfast: The Asylum Demon can't be frightened while it can see an allied creature within 30 feet of it

Multiple Attack: The Asylum Demon makes two attacks: one with its Ground Pound and one with its Hammer Drive.

Ground Pound: All creatures in a 15 feet cone from the asylum demon must immediately make a DC 12 Constitution saving throw. On a failure they are knocked prone and suffer 11 (2d8+2) bludgeoning damage, and their speed is reduced by 10ft until the start of the Asylum Demon’s next turn. On a successful saving throw the creature suffers half damage.

Hammer Drive: Melee Weapon Attack: +5 to hit, reach 10 feet, one target. Hit: 8 (1d10+3) bludgeoning damage. If the target is a creature other than construct, it must succeed on a DC 12 Constitution saving throw or lose 5 1d10 HP at the start of each of its turns due to the awful wound inflicted. Each time the demon hits the wounded target with this attack, the damage dealt by the wound increases by 5 (1d10). Any creature can take an action to stanch the wound with a successful DC 12 Wisdom (Medicine) check. The wound also closes if the target receives magical healing.

Long Range Hammer: Ranged Weapon Attack: +5 to hit, range 60 feet, one target. Hit: 8 (1d10+3) bludgeoning damage.