Valafar smirks at the man's useless attempt to harm him, "You should have run." The warlock strikes again, but as he does he calls upon the ugliness and darkness he knows resides within himself within all men and it manifests as a swirling cloak of flies biting and stinging any near him.

Spoiler: ooc
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Thirsting blade: 2 attacks

Bonus Action: Invocation Cloak of flies.

As a bonus action, you can surround yourself with a magical aura that looks like buzzing flies. The aura extends 5 feet from you in every direction, but not through total cover. It lasts until you're incapacitated or you dismiss it as a bonus action. The aura grants you advantage on Charisma (Intimidation) checks but disadvantage on all other Charisma checks. Any other creature that starts its turn in the aura takes poison damage equal to your Charisma modifier (minimum of 0 damage). Once you use this invocation, you can’t use it again until you finish a short or long rest.

He takes 4 Damage automatically at the start of his next turn.

Attacks

One.
(1d20+8)[15]

Damage: (2d6+5)[9]

two
(1d20+8)[26]

Damage: (2d6+5)[12]