Kirop was an Av Matoran resisting in Karda Nui in the form of an Onu Matoran. He was the leader of the Av Matoran until he was turned into a Shadow Matoran by a Shadow Leech attack.
Kirop, acted a Chirox's eyes when the Makuta was blinded by Matoro. He fought against Av Shadow Matoran strike team until the six Toa Nuva were teleported into Karda Nui and drove off the Makuta. Three of the Toa Nuva went to the Swamp of secrets to locate the Kanohi Ignika while three of the Toa stayed in Karda Nui to protect the Av Matoran. Kirop, was struck out of the sky by Toa Lewa and taken in for questioning by Kopaka though he never got the chance to. When Kirop awoke he was in a cell in Karda-Nui. The Toa were deliberatly talking about a false plan to attack the Shadow leach live, on the other side of the wall. Kirop broke out to warn Mutran of the attack which he beleived was real. The Toa followed him with three Av-Matoran. They Toa soon met Toa Ignika on the way and they all teamed up to attacker the hive, whick Kirop had unknowingly lead them to. There was a battle between Kopaka and Mutran and later one between the blind Makuta and Kopaka. The Toa managed to escape and destroy the Hive. Mutran was furious at Kirop and threatened to kill him had Antroz not stopped him. Kirop was later cured by a Klakk thanks to Takanuva and has since returned to Metru-Nui with the other Av-Matoran