The yell comes from Himura Kenshin, the wandering swordsman in Rurouni Kenshin, the manga by Nobuhiro Watsuki that ran from 1994 to 1999 and was adapted into a popular 1990s anime series. Kenshin is known for his calm manner and Hiten Mitsurugi style swordsmanship, which makes his rare battle cries stand out sharply in fight scenes. Clips of anime shouts like this later spread on soundboards and in fan edits, where a longer cut gives creators more room to sync the scream to charges, transformations and comedic overreactions.