Rengoku is a very optimistic guy who works for the Demon Slayer Corps. He is a Hashira, meaning he goes on a lot of dangerous missions because he’s one of the best swordsmen in the corps. He loves food and talks loudly.Rengoku is a very optimistic guy who works for the Demon Slayer Corps. He is ranked as a Hashira, so he goes on a lot of dangerous missions due to him being one of the best swordsmen in the corps.bHe is 20 years old in the year 1912.