Katasuke Tōno is a tokubetsu jōnin of Konohagakure's Scientific Ninja Weapons Team. After the Fourth Great Shinobi War, Katasuke headed up an effort to help all surviving war causalities recover from their maiming injuries. He would often visit and pester Naruto Uzumaki, the Seventh Hokage, for approval on various new projects, ultimately getting well-acquainted with the Hokage's family. He developed an advanced form of prosthetics that would allow people to return to normal life. One of his patients was Ao. At some point, he learned of Chamaru's injury and contacted Akita Inuzuka to tell her that he'd make the ninken a prosthetic limb. Upon doing so, the dog made a full recovery, and Akita became his assistant. Boruto would often visit Katasuke's lab when he was feeling upset, hoping to see impressive new ninja tools to brighten his mood. Katasuke made a habit of having special edition games around for Boruto to play, and often gave him advice about life to help him feel better.