Horn of Blood

Wondrous item, rare (requires attunement by a vampire)

This ancient, massive horn is made of tarnished bronze with ivory inlay. If you are a vampire and you sound the horn, it produces a subsonic noise that summons 2d6 + 2 sahuagin that willingly serve you for one week. Sounding the horn gives you one level of exhaustion. Any creature other than a vampire who sounds the horn gains two levels of exhaustion.