[[Fo]] spell available to [[Priest/Priestess]] at 30 [[Faith]]. Used to enchant [[spirit cottage]]s and [[spirit house]]s to allow them to send [[mail]] to other players.
The power and effect of spell is given in the bracket [x] Ranging from 0 to 99. The spell can be cast multiple times to try to improve the effect of it; failure does not destroy the mailbox. Success of casting the spell depends on your channeling skill. A higher power increases how keen the Messengers are to work for you (mail is reputed to be delivered faster if the mailbox has a higher cast on it).
Courier can also be cast on fountains and wells to turn them into [[wishing well|wishing wells]], which can then be used to make wishes by activating a coin and right-clicking the fountain or well. It is unknown whether the cast power affects the chance of the wish to come true.