Wondrous item, legendary (requires attunement)
While wearing this circlet of cold iron, your eyes grow pale and sharp, like a vulture. While wearing it, your Wisdom score increases by 2, to a maximum of 20. In addition, you have advantage on any Wisdom (Perception) or Wisdom (Survival) check you make that relies on sight or smell.
Hold Prey. The circlet has 10 charges and regains 1d6 + 4 expended charges daily at dusk. While wearing the circlet, you can use an action to expend 2 or more of its charges to cast the hold person spell from the circlet (2nd-level version, save DC 16). Alternatively, you can use an action to expend 5 or more of the circlet's charges to cast hold monster from it (5th-level version), using the same save DC. You can increase the spell slot level by one for each additional charge you expend. If each target is missing any of its hit points, the number of charges needed to cast the spell is reduced by 1. This version of the spell ends early on a target if you can't see it at the end of your turn, and while you concentrate on the spell, you can't willingly move away from a paralyzed target, unless that movement is also toward a different one.
Within the grooves, alcoves, and blind corners of the citadel, innumerable traps were hoarded. Traps designed to cut, to pierce, to sicken or maim, but never—save for the most foolhardy intruders—designed to kill.
So, many would find their way to the labyrinth's heart by stepping over the piles of bone and viscera...all to stand before the Carrion Keeper. Those who made it to his throne, despite their new scars, would look upon the gaunt form in his iron crown without fear. From him, they could request a boon, dredged from the secrets and treasures he had scavenged.
But those who wavered learned the truth of the citadel's traps, as the vulture's gaze rolled over them, hungering, and froze them from within....
And the Keeper would descend to feast, and his hoard grow.