Cozbinaer or Cozbi, in the Dungeons & Dragons roleplaying game, was the consort of the demoted lord of the 5th layer of Baator, Geryon. As of Fiendish Codex II, Cozbi was destroyed as a result of Geryon's demotion along with bailiff Gorson and the pit-fiend Fecor.
Cozbinaer is described as an exquisitely beautiful she-devil with fair skin, long green hair and a body reddening from the waist down. She also had long black nails, a slim pointed tail she would hang over one arm, and vampire-like fangs for canine teeth. Her eyes were scarlet.
Cozbinaer was perhaps the weakest and quietest of all Hell's duchesses. However, she took being called "Cozbi" by anyone not of her kin as a major offense. Any non-baatezu that did so was never seen alive again. She was extremely loyal to Geryon, and her devotion bordered closely to what mortals know as love. However, this very behaviour ended up being her demise, as did Geryon's faithfulness to Asmodeus.
Cozbinaer was exiled to Avernus along with her master and his loyal lieutenant Amon upon the Reckoning of Hell. As soon as they entered the layer, Geryon's followers were attacked by Levistus's followers who slew the major part of Geryon's court. Cozbinaer has been horribly wounded during these conflicts and then appeared as a zombie-like harridan whose body was covered in scars, skin grafts and withered flesh. Though she should have died long ago from her wounds, she was kept alive through profane magic and hellish technology and spent her time in a glass chamber where a poisonous yellow gas was funneled by tubes. If she had to leave this room, she wore a bizarre armored suit that contained the same gas, which was deadly to anyone but her. The location of the room itself was unknown.
The circumstances of her death are yet to be revealed. She either couldn't sustain herself any longer or someone eventually found the room where she laid and destroyed the apparatus.