Amulet of the Iron Heart

Forged from a melted-down soldier's medal, this pendant pulses faintly in rhythm with the wearer's heartbeat. The closer you are to death, the stronger the pulse becomes.

Your Constitution score increases by 2, up to a maximum of 20.

In addition once per long rest, when you drop to 0 hit points, you instead drop to 1 hit point and immediately gain temporary hit points equal to your character level.