Cursed Sword
Sam looked at the black colored single-edged sword. It is fully covered with black colored fog.
It is a Cursed weapon.
Cursed weapons are inherently weapons which are possessed by the spirits, but they will be considered cursed when a person who nurtures the spirit of a weapon couldn't control and gain acceptance of the weapon spirit which makes the weapon go astray and the cultivator's spirit would be devoured by the weapon spirit if he forcefully tries to wield it despite not being accepted by the weapon.
If it is only that then there is nothing much to worry about, but the problem is the cursed weapons which gained sentience will start nurturing themselves, they might nurture themselves with a certain element of neutral spiritual energy.
And when reached a certain level, they will have their inherent special move.