Alastor, The Radio Demon

Devil’s Sight. Magical darkness doesn’t impede Alastor’s darkvision.

Disarming Charm. While Alastor isn’t wearing armour, his AC includes his Charisma modifier.

Face For Radio. Any creature that attempts to view Alastor with divination magic such as with arcane eye or scrying must make a DC 21 Wisdom saving throw. On a failure, the spell ends and the creature takes 7 (2d6) psychic damage. On a success, the spell works as normal though Alastor's visage distorts constantly.

Fear Aura. Any creature hostile to Alastor that starts its turn within 60 feet of him must make a DC 21 Wisdom saving throw, unless Alastor is incapacitated. On a failed save, the creature is frightened until the start of its next turn. If a creature's saving throw is successful, the creature is immune to Alastor's Fear Aura for the next 24 hours.

Immortal Sinner. If Alastor is slain by any means other than by a holy weapon or radiant damage, his body reforms after 5 (1d10) days, regaining all his hit points and becoming active again. Alastor reappears within 1 mile of where he was slain.

Magic Resistance. Alastor has advantage on saving throws against spells and other magical effects.

Shadow Tentacles. Alastor can have up to four tentacles at a time. Each tentacle can be attacked (AC 21; 10 hit points; immunity to poison, psychic, and necrotic damage; vulnerability to radiant damage). Destroying a tentacle deals no damage to Alastor, who can extrude a replacement tentacle on his next turn. A tentacle can also be broken if a creature takes an action and succeeds on a DC 21 Strength check against it.

Spellcasting. Alastor can cast one of the following spells, using Charisma as the spellcasting ability (spell save DC 21):

At will: alter self, enlarge/reduce (self only), major image, prestidigitation, thaumaturgy

3/day each: bestow curse, summon greater demon, summon lesser demons

1/day each: seeming, summon fiend, teleport

Multiattack. Alastor makes four Shadow Tentacle attacks, each of which he can replace with one use of Crush or Fling.

Shadow Tentacle. Melee Spell Attack: +13 to hit, reach 60 ft., one target. Hit: 21 (2d12 + 8) force damage. Instead of dealing damage, Alastor can grapple the target (escape DC 21). Until this grapple ends, the target is restrained. Alastor has four tentacles, each of which can grapple one target and can't attack another target whilst grappling a target.

Crush. One object or creature grappled by Alastor must make a DC 21 Strength saving throw or take 39 (6d12) force damage on a failed save. Alastor can only target the same object or creature once per round with this action.

Fling. One Huge or smaller object held or creature grappled by Alastor is thrown up to 60 feet in a direction of Alastor's choosing and knocked prone. If a thrown target strikes a solid surface, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 21 Dexterity saving throw or take the same damage and be knocked prone.

Shapechange. Alastor magically polymorphs into a Medium mass of shadow, or back into his true form. While in shadow form, Alastor can’t speak, manipulate objects, or take any actions besides this action. Alastor is weightless, has a walking and climbing speed of 60 feet, can climb difficult surfaces including upside down on ceilings without needing to make an ability check, and can enter a hostile creature's space and stop there. In addition, if air can pass through a space, Alastor can do so without squeezing and he is immune to all nonmagical damage whilst in his shadow form.

Shadow Stealth. While in dim light or darkness, Alastor can turn invisible until he attacks, enters bright light, or until his concentration ends (as if concentrating on a spell). Any equipment Alastor wears or carries is invisible with him.

Shadow Step. Alastor teleports, along with any equipment he is wearing or carrying, up to 60 feet to an unoccupied space that he can see.

Parry. Alastor adds +5 to his AC against one melee or ranged attack that would hit him. To do so, Alastor must see the attacker and have an available Shadow Tentacle not grappling a target.