reveal
Adventurer
Another idea:
Regardless of where you put them in Eberron, if you do use the "they were responsible for the accident in Cyre" that's an easy way to not insert some of the more powerful Red Wizard NPCs. Maybe the most powerful Wizards were performing a ceremony/experiment and they were killed immediately in the blast. The rest of the Wizards left to hide and rebuild.
Regardless of where you put them in Eberron, if you do use the "they were responsible for the accident in Cyre" that's an easy way to not insert some of the more powerful Red Wizard NPCs. Maybe the most powerful Wizards were performing a ceremony/experiment and they were killed immediately in the blast. The rest of the Wizards left to hide and rebuild.