Shishou is Kino's mentor and the one who taught her how to shoot. She's settled in the forest now and doesn't travel anymore—a big shift from her past. Her real name is never revealed; "Shishou" is just the Japanese word for master or mentor, which Kino didn't even realize at first.
But here's the thing: she wasn't always a homebody. According to the final anime episode (which takes place earlier chronologically than most of the series), the gunsmith who made The Cannon told Kino that he gave the gun to a young woman who demanded everyone call her "Shishou." She was a troublemaker who drifted from country to country causing chaos wherever she went.
The light novels fill in more details about those traveling days. Multiple stories show her in her late twenties, moving around with a male student in a beat-up yellow car. The picture they paint isn't exactly flattering—both she and her companion were ruthlessly greedy, willing to hurt people for profit. It's a starkly different version of the settled, protective teacher Kino knows now.
Content compiled by AnimeList.moe from publicly available sources.
