Dark Side spirits work the same as most characters, retaining most of the
abilities and attributes it had when it was alive. Any attack that deals
physical damage will not harm a Dark Side spirit, nor can a Dark Side spirit
make direct physical attacks against living characters. Any Force powers
with physical effects (ie, alchemy, telekinetic kill, injure/kill,
accelerate healing in another, telekinesis, force lightning, etc.) are
ineffective when used by or against a Dark Side spirit . Any damage caused
by these powers is reduced to zero. Dark Side spirits receive a +3D bonus
on all hide, sneak, and search rolls that they make.Dark Side spirits have the following abilities in addition to those they had in life:
Manifestation
Being nonphysical, Dark Side spirits are not affected, nor can they affect, anything physical. When they do manifest, they can be seen and heard. In order to remain audible and visible, a Dark Side spirit must succeed in an Easy Strength roll once per minute. Failure indicates that the spirit's voice and likeness fade until it manifests again.
Possession
By using the power of Sith sorcery, a character opens himself up to potential possession by Dark Side spirits (see the "Sith sorcery" Force power). Dark Side spirits can also attempt to possess other physical bodies, but such an attempt grants the potential victim an Easy willpower roll to resist. If a Dark Side spirit attempts to possess someone unsuccessfully, it may not try to possess that character ever again.
Once a Dark Side spirit has possessed a body, it retains its own Knowledge, Perception, and Technical attributes in addition to its own skills, and uses the Dexterity, Mechanical, and Strength attributes, as well as any physical abilities, of its host. The Dark Side spirit can exit the body at any time. If the body is killed while possessed by the Dark Side spirit, the spirit is forced out but otherwise remains unharmed.
While a Dark Side spirit occupies a body, the body's original occupant is forced out and becomes, for all intents and purposes, and Dark Side spirit. It may attempt to repossess its former body, or can try to possess a different one.
Force Travel
Dark Side spirits can use the Force to instantaneously travel to any point in the galaxy, though there must be some form of Dark Side energy there to act as a sort of "beacon." The spirit must be familiar with the destination. To use this ability, the spirit must succeed at a Willpower roll, with the difficulty based on the distance traveled.