Kanku is an officer in the Fire Nation military, and the governor of the colony and military garrison at Ye Niu Bay in the former Air Nomad territories. He was known to have a store of accurate maps and charts, and was in good standing with Fire Lord Ozai.
Ruling over Ye Niu Bay with a firm fist, Kanku rationed the colony's stores of everything from food to medicine, as well as pressurizing all firebenders into service. He brutalized all who opposed him or questioned his authority. When the firebending actor Hong Shen refused to serve in the military, Kanku kidnapped his son, Hong Zhen, as leverage.
Soon after, newly banished Prince Zuko began a trek of the air temples to look for clues to the location of the Avatar. Heading toward the Eastern Air Temple, Zuko stopped at the Fire Nation port at Ye Niu Bay to procure supplies and maps of the surrounding area. However, Kanku, the colony's overseer and afraid of losing favor with the Fire Lord, denied his request. Zuko and Shen banded together and breached his garrison, and the two bandits successfully took off with several maps and his hostage, Hong Zhen.