kts.CrystalStop – end "crystal ball" effect (stop showing location of other knights)
kts.CrystalStop() 
If the current actor (as given by cxt.actor) is a knight, then the player controlling that knight can no longer see the position of other knights on their mini-map (in other words, the effect started by kts.CrystalStart is ended). 
If the current actor is not a knight, nothing happens.
None.
This is used as the on_withdraw function for the crystal ball tile.