Red Mage
Job Ability: Runic Blade
Duration: 1 min or until any spell is cast within range. (friend or enemy)
Recast: 1min
While wielding a blade (sword, dagger), a Red Mage can stop attacking/casting and intercept any spell cast within range of the effect. Intercepted spells have their effects canceled and the MP cost of the spell is absorbed by the Red Mage.

Used at the right time, the Red Mage could stop a potentially disasterous spell from damaging the group, and get a nice boost to their MP. They will have to be mindful of staying out of range of the other mages in the party, and good communication will be necessary with hybrid DD/Mages in melee range, such as the Paladin this is intended to help.
I mentioned this in the Runic Blade thread on the RDM sub-forums, but there's some tweaks that might be needed for that. Firstly the total damage done by the spell would have to be halved, and half of the MP cost of the spell would be abosrbed by the RDM. I only mention this because Runic as is would mean that one could possibly cheese spells that are supposed to kill a player or otherwise heavily damage the party as part of the encounter mechanic.