Are liches their own beings or are they like ghosts who possessed a dying person and never got around to healing the wounds in return for using magic still?
Hmmm... Excellent question...
To my mind, trying to combine current lore with most of the fantasy lich description, liches are ghosts, that have achieved great powers, that create phylacteries, using special crystals, that allow them to take over a completely dead body, which gives them more complete access to their powers than sharing the body with a mostly dead person, as My Name is doing. Then they reinhabit their old body. This gives them the most access to undead powers, while also acting as a form of immortality. They gradually use any number of herbs, surgeries, and magics to reconstruct their body to a less decomposed form, but their flesh is permanently marked by its time spent dead.
Feel free to criticize this. I'm open to revising it. No liches known in the world yet, so this lore is stuff that will come up later. I'm writing religion in soon, and it could also relate to that if you think this is a bit of a stretch.
What is the extent of a ghosts power? I mean what would a "level one hundred" ghost be able to do?
A very well developed ghost could have any number of abilities. Because there has been
a lot of interest in this subject I'll add it to my to-do list to flesh out the idea further, but I had at one point drawn up a number of classes. One was focused on controlling people, not through possession but more of manipulation. Another was an anti-mage, focused on sapping the strength of mages and neutralizing them. The third was a mage, focused on crystal related abilities and maintaining a large number of charges. The final was a combat based one, using crystals to give itself a limited manifestation that allowed for some direct combat.
These trees could all be fairly fully developed, meaning experienced ghosts could lead cults of followers, devastate manatic enemies, wreak havoc with their own magic abilities, or become some sort of ghoul that fights.
Again, as always, thoughts are welcome. This project will be lower on my to-do list, so theres plenty of time for you guys to critique this idead.