If it turns out that RDM gets locked behind a Special Snowflake Wall like BLM/WHM, I have a guess that the lore could possibly be something like... a separate sect of casters during the time of the War of Magi tried to combine the two warring disciplines and ending up creating something that was eventually refined into Red Magic, only to be shunned and/or forgotten due to [insert conflict here].
If the job is written in such a way that its more accessible to the average adventurer, however? I'd put my money on Sharlayan like others have proposed. (Or maybe we're all wrong and it's from some place we'd never even expect! I don't freakin' know.)
If the job is written in such a way that its more accessible to the average adventurer, however? I'd put my money on Sharlayan like others have proposed. (Or maybe we're all wrong and it's from some place we'd never even expect! I don't freakin' know.)