Tatsuma Sakamoto 坂本辰馬

Sakamoto is a former member of the Joi. He is a good-natured man and optimistic to the point of being ridiculous, even in the most dangerous situations. His favorite phrase is "AHAHA! It must be _____". He also has a tendency to misspell names; he calls Gintoki "Kintoki". Gintoki often corrects him, citing that if he were named Kintoki, they would be in some kind of hentai anime (because 'Kin' from 'Kintoki' instead of 'Gin' would make the title 'Kintama', which means 'testicles' instead of 'Gintama', which means 'silver soul').

Despite his goofy nature, Sakamoto is actually a successful businessman in the galaxy. He believes that business is a way of protecting his country. He has a private, well-equipped defensive business fleet. He believes that sacrifices should be made for the good of the community, which is why he chose to abandon his comrades on Earth to travel into space. Sakamoto is shown to be skilled with a pistol in an anime filler episode.

His name is based on the historical character Sakamoto Ryouma. He speaks in Tosa-ben, much like the inspiration for his character.