Pawoo Nekoyanagi, older sister to Milo Nekoyanagi, possesses dark-blue eyes and long, straight black hair extending past her waist. Her athletic physique features an E-cup bust, though rust initially afflicted her left side until fully healed by Rust Eater mushrooms.

As captain of the Imihama Watch, she hunted Bisco Akaboshi, convinced he was a mushroom terrorist spreading rust. She confronted him in combat, dismissing his claims that mushrooms consumed rust. After Bisco defeated her and took her to Milo, she awoke to find Milo had departed with Bisco seeking the Rust Eater for her cure.

Determined to retrieve Milo, she pursued them. En route, she saved a couple attacked by a monster spider. The couple later tried to poison her, revealing they preyed on travelers. After trapping themselves in a shelter to escape her, she continued her pursuit.

She rejoined Milo and Bisco during their battle with a Pipe Snake. Captured by the creature, Milo freed her, forcing a temporary alliance with Bisco to rescue Milo. Witnessing the Rust Eater activate through Bisco's blood challenged her beliefs about Mushroom Keepers. Kurokawa attacked, stealing the Pipe Snake and shooting Bisco with a rust bullet.

Choosing to deliver the synthesized Rust Eater medicine to Jabi instead of taking her dose, she kept the cure secret from Kurokawa. Returning to Shimabuki Base, Kurokawa captured and tortured her for the Rust Eater's secret. She resisted, urging Milo and Bisco to flee. Jabi later rescued her, and she aided the fight against Kurokawa's forces. After Kurokawa's apparent death, she helped recover Bisco's body and supported Milo.

During the Tetsujin incident, she deduced its armor could be breached without triggering self-destruction. Extracting a reward promise from Bisco, she used Actagawa to reach the Tetsujin's head, splitting its armor to expose Kurokawa, enabling Bisco and Milo to defeat him.

Following these events, her rust fully cured. She became governor of Imihama, declaring independence from the Japanese government, ending Mushroom Keeper persecution, and removing Bisco's wanted status. She later married Bisco. During her subsequent pregnancy, she and Bisco searched for "Ghost Hail" mushrooms in Hokkaido but were abducted by a flying vessel called the Ark. They confronted a new enemy, President Meah, and escaped with their newborn child, Sugar Akaboshi.

Her combat skills include masterful polesmanship and skilled hand-to-hand combat. Her surname combines "cat" (猫) and "willow" (柳).