Agent of Erebos

Bounty of Erebos. If the agent is aware of a Returned mask, it spends its turns trying to banish the person or monster carrying that mask.

Evasion. If the agent is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, the agent instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.

Immortal. The agent can't die as long as at least one memory or record of it exists. If it would die, it falls unconscious instead.

Innate Spellcasting. The agent's innate spellcasting ability is Charisma (spell save DC 11, +3 to hit with spell attacks). It can innately cast the following spells, requiring no material components:

At will: banishment

Magic Weapons. The agent's weapon attacks are magical.

Spell Nature. In addition to being a creature, the agent is a 4th-level divine transmutation spell with no target.

Starlight Form. The agent glows with the soft light of the night sky, shedding dim light in a 15-foot radius.

Telepathic Bond. If the agent was created by a god, then while the agent is in any of Theros's three realms, it can magically convey what it senses to that god.

Undead Nature. The agent doesn’t require air, food, drink, or sleep.

Banish Dead. The agent banishes a creature wearing or holding a Returned mask to the Realm of the Dead using banishment. Any objects the creature was carrying or wearing fall to the ground. As a bonus action, the agent loots any Returned masks the target was wearing or carrying and strings them onto its cord.

Unarmed Strike. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 bludgeoning damage. This is a magic weapon attack.