Kharash's Promise
Wondrous Item, Instrument, Artifact (Requires Attunement)
Tol Kharash, the Horned King, overlord of tyranny, demands that his minions revel in domination, fear, and the suffering of the downtrodden. During his campaigns in the Age of Demons, Tol Kharash shaped an artifact that would announce his coming across the Barrens; a harbinger of cruelty.
Kharash’s Promise is a 3-foot long warhorn forged of demonglass and black iron. A trickle of boiling blood constantly drips from its widest end. While holding this Horn, you gain a +3 bonus to spell attack rolls and to the saving throw DCs of your Bard spells.
Random Properties. This Artifact has the following random properties, which you can determine by rolling on the tables in the “Artifacts” section of the Dungeon Master's Guide:
Surety of Dominance. While attuned to the warhorn, no creature can assert its influence over you. You cannot be Charmed or Frightened. If a creature targets you with a magical effect that would cause you to be Charmed or Frightened, that creature takes 4d10 Psychic damage.
Thaumaturgic Clarion. If you blow Kharash’s Promise, the sound it produces can be heard by all creatures within 1 mile.
Promised End. As a Magic action when you blow the horn, you can choose one creature that you can see and that can hear the horn to suffer a painful and inevitable end. The target must make a DC 20 Charisma saving throw. On a failed save, the target’s Hit Point maximum is reduced by 1 at the start of each of its turns until it dies, you die, you are no longer on the same plane of existence as the target, or the effect is ended with a Wish spell. Once this property is used, you cannot do so again until 13 days have passed.
As a Bonus Action while affected, the target can choose to confront the source of its inevitable end, teleporting to an unoccupied space within 5 feet of you.