A ghost can "live" for a very long time as they can remain on the Material Plane as long as their willpower allows them, though they usually pass on after they fulfill a goal they could not accomplish in life.

Your creature type is undead. You do not require air, food, drink, sleep and you are immune to being poisoned, poison damage, and diseases. Your ghostly form still takes damage from various sources as it exacts a mental toll on you, making it harder for you to keep your form planted into the mortal plane.

Thanks to your ethereal form, certain advantages have been granted to you. You may now move through any creature or object as if it were difficult terrain, taking 1d10 force damage if you end your turn inside a creature or object.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

Ghosts have no weight and are as tall as they were in life. Your size can either be Small or Medium.

Your speed is 30 feet. You always hover 1 feet over the ground, but can't fly. If you end your turn more than 1 feet over the ground, you start falling.

An ability score of your choice increases by 2 and one other ability score increases by 1.

Trying to complete the pendant goal they have, most yurei have a lawful neutral alignment. Although yurei tend to retain the moral alignment they had in life, it is not rare that some of them change alignment into good or evil.