system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Can Sith lords come back in spirit form like the Jedi masters can?
gpt
As of Canon, no they cannot. The ability to become a Force Ghost is not something that can be achieved by one tainted by the Dark Side. Yoda even remarks that the phantom Darth Bane he meets was no more than an illusion.

In Legends, oh totally. Pretty much anyone powerful who was Force Sensitive could linger beyond death as some form of spirit.