Short answers, pulled from the story.
Rurouni Kenshin follows Himura Kenshin, a former assassin known as Hitokiri Battosai who, after the Bakumatsu, vows never to kill again and wanders Japan protecting the innocent with a reverse-bladed sword. The story begins in 1878, the eleventh year of the Meiji era, and follows his efforts to atone for his violent past while facing old enemies and new threats.
Rurouni Kenshin was written and illustrated by Nobuhiro Watsuki. It was serialized in Shueisha's Weekly Shonen Jump from the 12th of April 1994, to the 21st of September 1999, and its 255 chapters were collected into 28 tankobonvolumes.
By December 2019, the Rurouni Kenshin manga had over 72 million copies in circulation, including digital releases, making it one of the best-selling manga series of all time.
Five live-action films were produced, all directed by Keishi Otomo and starring Takeru Satoh as Kenshin. The first film was released on the 25th of August 2012, and the series ended with Rurouni Kenshin: The Beginning in 2021. The films were produced by Warner Bros. with production handled by Studio Swan.
Hideaki Sorachi cited Rurouni Kenshin as a major source of inspiration for Gintama. Koyoharu Gotouge drew on Kenshin's design when creating Tanjiro Kamado for Demon Slayer: Kimetsu no Yaiba. Masashi Kishimoto, creator of Naruto, read Rurouni Kenshin during college and felt it set a standard he struggled to match.
The sakabato, or reverse-bladed katana, symbolizes Kenshin's oath never to kill again, with the cutting edge facing inward rather than outward. Marco Olivier of Nelson Mandela Metropolitan University noted that this pledge is frequently tested throughout the narrative as other warriors challenge Kenshin.