Kol Yabu, a reader, was an adherent of the Undying Flame, the religious order of the Lover Gods. Yabu's physical form was deliberately mutilated via ritualistic burning and scarring, resulting in a dualistic appearance; one half resembled a male, embodying Yun-Q'aah, while the other half took on a female form, symbolizing Yun-Txiin.
During the time of the Yuuzhan Vong War, Yabu functioned under the command of Vaecta, a priestess, on board the flagship Sunulok of Warmaster Tsavong Lah. The apostle was inside the Sunulok's Glory Room for Lah when Nom Anor, an Executor, came back from the planet Coruscant following his speech to the Senate of the New Republic. When Anor revealed that Jacen and Jaina Solo, young Jedi, were twins, Yabu insisted he verify this information. Subsequently, Anor inquired about the perspective of Yun-Txiin and Yun-Q'aah on the death of just one twin. At first, the Undying Flame follower evaded the inquiry, merely stating that the Lover Gods did not call for sacrifices. However, when Lah pressed him, Yabu conceded that such a circumstance would destabilize the Great Dance.
Kol Yabu made his debut in The New Jedi Order: Star by Star, a novel from 2001 authored by Troy Denning.