Karsh is rather touchy about saying on that.
But for his people, ghostliness is a norm.
Or it was in his time.
Not so much a thousand years after his initial battle and ‘end’ with the Archon.
(By his count, he’s ‘died’ at least three times. The time of having Lady Bouvredi bash him with the tankard doesn’t count.)
This is complicated by the meddling of the Eternal, and Karsh status as a shape shifter.
A recurring ‘face’ in the story, Abilene the Seer, was known as Abilene the Shieldkeeper in her time as she was the warrior, and her King, Nev Dralmat, was a bit of a scholar/tinkerer.
In the story, she’s a ghost, and quite a troublesome one at that.
Arselen starts off the events in the beginning of the tale by taking refuge in the temple, and asking for a hero.
Just so happens that down in the crypts, the Eternal has a hero up his sleeve, Karsh.
(Karsh thought he was dead, at least wasn’t that what happens when one falls in battle against a necromancer? And then the Eternal goes and wakes him up from his nice peaceful rest on that stone bier.)
As a writer, I don't make things up as I go along. I make things up, and watch to see how they go along.