Cartouche of Ambition

This amulet is carved from lapiz lazuli with scenes of pain and sacrifice, and seems to glow jet-black from within. While attuned to this cartouche, when you deal damage to a creature, you can use your reaction to automatically regain 1d4 hit points. You can use this ability three time per long rest. In addition, once per long rest you can use a bonus action to poison a weapon you are holding; the next creature hit by an attack from that weapon automatically takes an additional 1d4 poison damage, and must make a DC 12 Constitution saving throw or become poisoned. A poisoned creature can repeat the saving throw at the end of each of their turns, ending the effect on a success. While attuned to a cartouche, any other cartouches do not count towards the number of items you can attune to. For every other cartouche you are attuned to, the hit points restored and poison damage each increase by an additional 1d4, and the DC of the saving throw to avoid being poisoned increases by 2.