Spells in Galaq

The party is well above the current level of understanding in this land.  There are bits and pieces of arcane learning to be found, but it will be far more difficult to find them.  Fifth level spells will need to be researched in order to be found.  Lórien will have an easier time of it, but will still need to find them in the libraries of the Loremasters.  Each discovered spell will require a successful search and 100 gp worth of resources.

Marcillus will have a more difficult time.  The Lightbringer has no power in this land, and limited communication abilities.  That leaves three options: 

1. Use the spells of the Lightbringer with a chance of failure
2. Find a god in this plane who will grant spells.
3. Research new spells at the Loremaster

A distant fourth option is to kill a god and gain his knowledge, but this is no easy task.  Unless fifth level cleric spells are granted by a god of this realm, they will all require a material component.  Finding them at a loremaster will require a hard search and 200 gp worth of materials to transcribe and learn.