Since the PCs haven't yet stepped foot on the Red Planet, I have only very vague notions of what the place is like, but one thing I do know is that many of D&D's weirder monsters have their origins on Areon. A few examples:
- Carrion Crawler: The larval form of a weird moth-like creature native to Areon, whom the Eld regard as pests.
- Displacer Beast: A predator from the Red Planet, kept as pets and guard animals by many Eldritch aristocrats.
- Doppelganger: Shapeshifters with some strange relationship to the Eld, who routinely employ them as spies and assassins.
- Rust Monster: An Areonese (?) beastie used by the Eld as living azoth detectors; that they also destroy ferrous metals, including enchanted examples of such, is just a bonus.