The spell can be cast anywhere across Gielinor only if the ensouled head is obtained as a drop from the respective monster, and using it within a certain time frame in the area it was killed in.
Players who do the following will have to cast the reanimation spells within range of the Dark Altar:
- Obtaining ensouled heads via trading with other players
- Teleporting away after obtaining the ensouled head as a drop
- Waiting too long before casting the spell within the area where the ensouled head was obtained