Seal of Solomon

Ring, very rare, requires attunement

This simple signet ring is silver with a copper lining and a symbol of a fist etched on the inside. Once attuned the ring grants you powers of a demon; you gain resistance to fire and imbue any weapon you wield so that it deals fire damage rather than its normal damage.

Furthermore, as an action you are granted ability to charm demons, which you can do once per short rest. The demon must succeed on a DC 15 Wisdom saving throw or be charmed by you for 2 hours. While charmed in this way, the demon regards you as its trusted leader. If harmed by you or your companions, or commanded to do something contrary to its nature, a demon ceases to be charmed in this way and will be very cross.