"Another one squashed beneath your boot
dashed to pieces with your saber
not even a name to you
a hurdle to gold was on the table
a moat filled with blood you were happy to drain
another one that wouldn't be tricked by your slippery brainsssss
They came to me, after
ssaid, your tassk issss finished.
Sssssserved your god well, reward for matter
to cower in hisssss pressencessss diminished.
No. What issss thissss word, "No?"
No, I ssssaid. A new tasssk hassss begun."
I gripped the stone face with my last strength, a bead of sweat dripping off my nose, down countless distance, likely on to the sleeping beast below.
"Well, prattling spirit, help me out of this chasm or shove me down into it, but do shut up."
-excerpt from the unedited journal of Porpulent Grantz, explorer, King's Agent, and appointed Savior of the Far Isles.
Ghosts as a monster in the Manual are a fine scary beast if run well, but that pile of stats and abilities does not speak to the ghost stories of the heart.
Adventurers are responsible for a great number of souls crossing from life to un-life, from here to there, perhaps more than their enemies, even.
Being responsible in the real world for maintaining much contemporary equipment that transmits data from here to there, I have the terrible knowledge of how feeble it all is, how many mistakes happen per second that our equipment ignores. Whether the passage of souls is bureaucracy, like unto technology, or a natural process in your worlds, there must at times be mistakes. Perhaps the passion for vengeance overrules sense and order.
It seems inevitable that some adventurers, at some time, will become haunted by a damned soul. Whether touching the wrong thing or smiting a soul that burns hot, the living gains a passenger. This passenger likely wants to see the adventurer suffer, but this creates a paradox; the adventurer must succeed on some occasions to suffer on others. It should also be mentioned that the dead are insane.
Haunted - the PC afflicted so rolls an additional d6 when rolling Ability Checks, Saving Throws, Spell Checks, and To Hit.
1-2 : subtract the number rolled from the check*
3-5 : no effect
6 : add +1 to the check
*after a result of 1 or 2, the player may choose to stop rolling the extra die for the next hour of real time. The ghost is exhausted, disgusted, satisfied; the dead have trouble telling those conditions apart.
The Haunted PC may ask the ghost questions about things it knew in life. On a successful CHArisma check, the Ghost might answer.
It is heavily recommended that if the player does not occasionally role play this haunting, the GM does.