Witch of the Demon Seas by Poul Anderson

Day crept past in a blindness of rain. Twice Xanthians brought them food, and once Corun and Imazu ventured down the ramp to find their way barred by spear-bearing reptiles. For the rest they were alone.

It ate at the nerves like an acid. Shorzon sat stiff, unmoving on a couch, eyes clouded with thought; his gaunt body could have been that of a Khemrian mummy. Imazu squatted unhappily, carving one of the intricate trinkets with whose making sailors pass dreamy hours. Corun paced like a caged beast, throttled rage mounting in him. Even Perias grew restless and took to padding up and down the antechamber, passing Corun on the way. The man could not help a half smile. He was growing almost fond of the erinye and his honest malevolence, after the intriguing of humans and Xanthi.