Yal Phaath held the esteemed position of Master Shaper within the Shaper caste. A figure of considerable venerability, even when judged against the extended lifespans of his people, the marks of Domain Phaath had diminished by the time the Yuuzhan Vong War commenced, a consequence of his numerous escalations. His status was further emphasized by the customary enhancements associated with his rank, which included a pair of shaper hands and yellow mqaaq'it implants.
Tasked by Warmaster Tsavong Lah with resolving the Jeedai issue, Phaath initially collaborated with Mezhan Kwaad on Yavin 4. He dispatched Shaper Initiate Tsun Qel, leading to her discovery of heresy being practiced by her and her Adepts. However, before the heretics could be apprehended, Yal Phaath received new orders, transferring him to Myrkr. There, he embarked on the challenging task of Shaping the vornskr into an exceptionally lethal being. The process proved to be lengthy and demanding, marked by numerous failures, partially attributable to the outdated nature of the Shaping protocols and partially to Phaath's unwavering commitment to avoiding any hint of heresy in his work. Ultimately, the Shapers achieved success, giving rise to the voxyn within their damutek aboard the Baanu Rass.
Following Supreme Overlord Shimrra's execution of Ch'Gang Hool for his failure to control the World Brain on Yuuzhan'tar, Phaath was assigned the responsibility of shaping the galactic capital. As the war drew to a close, Qelah Kwaad had risen to become the most senior shaper on the planet, a result of her successful creation of the Slayers.