Souledge

The moment an individual picks up Souledge, provided it is not already bound to another, the individual becomes cursed. The cursed individual may sheath Souledge, but may not remove  their sword belt. If others attempt  to remove souledge or its sheath, the cursed individual becomes aggressive, even to the point of becoming violent.  

Souledge  talks to the cursed individual, using the voice and mentally projected form of the last person to own it. It feeds on souls and will try to seduce the cursed individual towards violence. Whenever the cursed individual  enters combat they must make a wisdom saving throw or be forced  to use souledge  as their primary weapon for that combat. The DC for this wisdom save is DC14. Each time the cursed individual fails a save, the DC is increased by 1 the next time they enter combat.

Souledge takes the form of a weapon the wielder is familiar with. Souledge gives the weilder a -1 to hit and a +3 to damage rolls. If the cursed individual misses an attack, they themselves  take the damage.

If the cursed individual dies wile wielding  Souledge, their soul is trapped  in the  blade and they can choose to add +1 to hit or +1 to damage to Souledge.

The curse can either be removed  by the Remove  curse spell or the Wish spell.