A sea creature of Tra Sakinig similar to a blue marlin, bred and ridden by the Speghti as cavalry mounts. Every House's Shock Cavalry rides them (see Speghti culture), and they are fast enough to stay ahead of a Speghti on foot.

Ms Antinomy was given the Ibui she had ridden on the scouting trip at Fortress Trulia as a parting gift. It was then kept alive, semi-secretly, in the Hercules' water-reclamation tank, until Asoloi Tui asked to buy it and take it to the sea on Calypso. Tui also planned to take no Speghti sea creatures to a Calypso colony other than Ibui.