Dubious Soul:

The wielder of the Dubious Soul increases their Prowess by 1, and may add a +1 bonus to all mech-rps. For each session this artifact is equipped, there is a 50% chance that their heir will lose a health state at their creation. To a maximum of 450%, rolled at the heirs creation. If 450% chance is reached, this artifact is destroyed, killing the wielder.