Binders in the campaign

A player asked me if he could play a Binder (from the Tome of Magic) in the WotBS campaign.

I haven't looked into the Binders (and their "needed" cosmology) too much, but could anyone with some more insight on them (and the campaign) tell me how good they would fit?

I don't see why they couldn't work. Their cosmology requirements are all "behind the scenes" so to speak. You don't really need to worry about adding in new gods or anything because the vestiges are intentionally sort of vague, with less than godlike powers. It shouldn't really require any extra work on your part, I don't think. I would be curious to see how you dealt with it, though. I'm going to be starting my own WotBS game next week, and I'd like to see someone in my group try a binder. I've never seen them in play, so here's to hoping!

Also, if you felt adventurous, you could come up with a vestige for the Stormseeker(?) Eagle that had its heart torn out by the Flamebringer(?) Dragon in Gate Pass myth. I thought about doing so myself, I just haven't gotten around to it.