Aquatic race whose compact rebreather technology can be worn externally or grafted inside a body.
The kua-tin's practical legacy in this chapter is hardware. The Kua-tin Rebreather taken from Loita's body after Mordecai assassinated her is tiny, about the size of a large bracelet, and Carl assumes it is far too small to be useful.
Edgar corrects him — not for where they mean to put it — and Rosetta confirms that these devices are designed to work either internally or externally. Sewn into the bronchial tube, it lets Louis survive on the naiad heart and lungs taken from Princess Lunette.
Source race of the breathing technology that makes Louis's transplant viable.
Also appears in books you've already read — spoiler-safe to their endings: