How would a PC be able to remove a ghost or a spirit from a location? Would killing it suffice, or would they need to cast the 5th level spell I forgot the name of? Is there some other ritual to be performed?
In general undead are gone once defeated unless they have a trait that says otherwise, or the DM has ruled that they will return, in which case the effect that makes them return should say how to prevent it (for example, a revenant is gone when it slays its target, a year passes by, or a wish is used). For non-specific issues, ceremony is likely a suitable spell for laying the dead to rest after its manifestation has been defeated.
How would a PC be able to remove a ghost or a spirit from a location? Would killing it suffice, or would they need to cast the 5th level spell I forgot the name of? Is there some other ritual to be performed?
They could possibly even try to negotiate with it if you want them to have that option.
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In general undead are gone once defeated unless they have a trait that says otherwise, or the DM has ruled that they will return, in which case the effect that makes them return should say how to prevent it (for example, a revenant is gone when it slays its target, a year passes by, or a wish is used). For non-specific issues, ceremony is likely a suitable spell for laying the dead to rest after its manifestation has been defeated.