Oh, I admittedly had put much more thought in Hades playing a larger role--the cop out answer would be he's sort of like The Emperor Across the Sea, but instead of it being a distant father, it's a patient husband. A more fun idea would be instead of the Carolmene Empire and Tash, it could be a different culture who does worship Hades (I dunno, Terebinthia, maybe? No one really writes about them), and are trying to invade a weakened Narnia. Except the same way the Tash isn't putting up with his followers' nonsense, Hades would also have no patience and just try to kill them all for the audacity of summoning him to bother his wife's people.

It'd be fun, but harder to do a one-to-one swap of characters. Mostly for a tltwtw swap, I'd probably keep references to him at a minimum and then he could show up for a sequel.