Skelemirror

Wondrous item (skeletoy), uncommon (requires attunement)

Skeletoys are objects that Underhell fiends use as their monstrous tools. Most of them are made up primarily of spinal columns and skulls, but other configurations also occur. Generally, mortals can’t use one of these items effectively unless they trick the skeletoy into believing they are fiends or acting under the direct orders of fiends; in such a case, the item will not oppose them until it realizes the truth. All skeletoys obey any fiend who commands them, or a minion acting on that fiend’s behalf. In case of conflicting commands, the skeletoy obeys the highest-ranking individual to give a command. All skeletoys have the same special purpose: to further the fiendish invasion and protect all Archlords.

This flat shoulderblade or skull is framed in smaller bones and coated in a gleaming sheen of black ichor. It is primarily used to communicate with other bearers of skelemirrors, but can, in theory, contact anyone, whether they have a mirror or not. As an action, you can use the skelemirror to cast sending. Once the mirror is used to target a creature not also holding a skelemirror with this spell, the mirror can’t be used to do so again until the next dawn.

Sentience. The skelemirror is a sentient neutral evil wondrous item with an Intelligence of 13, a Wisdom of 15, and a Charisma of 11. It has hearing and darkvision 90 ft. Its passive Wisdom (Insight) and Wisdom (Perception) scores are each 15.

The skelemirror can communicate telepathically with any creature touching it and can speak, read, and understand Abyssal and Infernal as well as any language known by the creature it is currently attuned to.

Cursed. If the skelemirror opposes you when you attune to or use it, it can choose to curse you. This reduces your hit point maximum by 1d10 immediately after you attune or your message is sent, as the skelemirror slowly drains away your soul. This reduction lasts until the curse is broken. All attempts to be rid of the mirror, break your attunement, or restore your hit point maximum fail while you are cursed. A remove curse spell or similar magic breaks the curse and ends your attunement. The skelemirror can reduce your hit point maximum by another 1d10 each time you use it. If your hit point maximum is reduced to 0, you die and your body becomes a void maggot at the next sunset. Once you are no longer attuned to the mirror, a lesser restoration spell, similar magic, or a long rest restores your maximum hit points.

Personality. A skelemirror is sniveling and officious. If the skelemirror can understand its attempt, a creature can scare the skelemirror into serving it without conflict until the next dawn with a successful DC 15 Charisma (Deception or Intimidation) check as an action, so long as it is not obviously going against the skelemirror’s primary purpose. On a failed check, that creature can’t make the attempt again until the next dawn and any other non-fiend has disadvantage on attempts to use the same skill to influence that skelemirror.