Amulet of Shared Life

This delicate looking, multifaceted glass amulet projects rainbows across the room when the light catches it. In times past, elven nobility would sometimes receive these as gifts for especially celebrated marriages.

While attuned to this item you can use an action to designate another creature as your partner and tie your life essence to theirs. If either you or your partner take damage that would reduce one of you to 0 hit points, the other one can use its reaction to take half the damage dealt and leave their partner with 1 hit point instead. This damage cannot be reduced or prevented in any way.

After using the amulet in this way you may not do so again until you finish a long rest.