Ah, Oghma smiles upon your thread, Ry:
The PCs and their demons
Ardra: A Lemurian Hydragogue, slayer of a kinsman, searching for his stolen son… (John)
Ardra’s demon is Sherka: A Witch-Lord and kinsman of Ardra and kidnapper of Mahendra, Ardra’s son. Now a severed head, advising Ardra in his search, while hungering for human remains…Hamaan: A gladiator, his family murdered so he would be the last of his kind, seizing Black Rock for himself… (Mike)
Hamaan’s demon is Tacitus: Skull and last remnant of a great king of Thunder Lizards, aching for violence, seeker of dominance…Uzal: A freakish half-gray, braving the Wastes, hoping the Damsel Messiah might save its friend and teacher, the famed dictionarist… (Peter)
Uzal’s demon is Leviathan:The bones of a great whale, swimming through sands, rising and falling with crushing force, and creating terror, demanding sacrifices of water. Bound early by Uzal so that he might survive the wastes, a mighty Demon of the Ocean…
Githyanki Diaspora 
Sherka: A Witch-Lord and kinsman of Ardra and kidnapper of Mahendra, Ardra’s son. Now a severed head, advising Ardra in his search, while hungering for human remains…
Awesome.
Wow. The Leviathan demon is shit-hot.
Yeah, the Leviathan is great too – I picture the huge skeleton on Tattooine in the original Star Wars. I just especially like the talking severed head as sidekick thing. In an old D&D campaign of mine, there was a priest who has a whole bookcase of preserved severed heads for necromantic purposes.
Leviathan is a huge pain, getting and wasting water on Marr’d is a pain in the ass compared to feeding a head some thumbs.
Hamaan’s demon Tacitus ain’t bad either, but I think it’s about to be overshadowed by the fact that Black Rock is demanding to be bound RIGHT NOW.