Kiaphet Amman'sor was a representative of the Xindi-Aquatics on the Xindi Council in the 2150s. She was a member of the wealthy and powerful Ibix Dynasty, and her opinions carried great weight with the rest of the Council. She was often the peacemaker on the Council, attempting to calm the dissension that often arose. She was very concerned that in-fighting would tear the Council apart.
Amman'sor was at first against building the Xindi weapon to destroy Earth. It was not until the Guardians presented a visual recording of Humans destroying the new Xindi homeworld that Amman'sor was finally swayed. (ENT: "The Council")
Amman'sor rejected Dolim's plan to develop a bio-weapon to destroy the Humans, considering it too dangerous. However, Amman'sor stated that if the weapon being developed by Degra did not work out, she would be willing to consider alternatives. Once Rajiin acquired the necessary information to develop a bio-weapon, Amman'sor voted that they develop both weapons simultaneously. (ENT: "Rajiin")
When Captain Jonathan Archer came before the Council on February 12, 2154 to present his case, Amman'sor was at first unswayed by his evidence. However, once Archer showed the Council a biometric hologram, Amman'sor agreed to delay the launch of the weapon. (ENT: "The Council")
When the Reptilians and Insectoids stole the weapon, Archer confronted Kiaphet and the other Aquatic councilor aboard a Xindi-Aquatic cruiser. Three hours later, they agreed to help intercept the weapon in exchange for Archer's ship disabling the spheres, but their cruiser was destroyed by spatial anomalies in the subsequent battle. (ENT: "Countdown")
Kiaphet Amman'sor was the only female of any Xindi species seen on screen. She, like all Xindi-Aquatics, was a computer-generated character.
The final draft script of "The Council" didn't specify which of the Aquatics was to be identified as "Kiaphet Amman'sor" (unlike with Jannar and Dolim). In the pronunciation guide from the same script, the character's name was phonetically notated "KY-uh-fet ah-mahn-SOOR".
The novel Last Full Measure gives her full name as Qoh Kiaphet Amman'Sor.