The ring is a simple gold ring encircling a black diamond. In the middle the diamond is pure darkness and unsettling to look at for most.
The ring ajusts to the finger size of its wearer, it must be worn on a finger to gain its benefits. The wearer also feels the presence of another beeing in it.

During a long rest you can choose one of the 2 following settings for the ring which both expend 1 charge per use. The user needs to touch the diamond for it to activate.

a) As a bonus Action you can gain 1d4+1 Temp. Hit points, the ring glows red while those are active.
b) As a reaction you can gain +2 to AC when you think about it until you forget about it or are out of combat, this dosn't stack with other AC boosts or itself. Here the diamond becomes transparent and a black mist forms around the user, while active.

The ring can hold 2 charges regain all of them at midnight. if it recharged during a new moon it gains 1 extra d4 or one extra +1 to AC (+3AC or 2d4+1 for the following day)

Notes: Cleric or Paladin, Sorcerer