Appearance: A one-eyed handsome man characterized by a bandage wrapped over his left eye and a glamorous purple kimono with a butterfly pattern. He frequently uses a kiseru pipe. Alias: "The Most Dangerous Man among the Joui Patriots." Past: A childhood friend who studied alongside the protagonist Gintoki Sakata and Kotaro Katsura at their mentor Shoyo Yoshida's temple school. Difference from Gintoki and others: After the Joui War, driven by the sorrow of losing his mentor and despair toward the world, he began terrorist activities against the Bakufu and Amanto (aliens) to destroy the world. Consequently, he parted ways with Katsura, who aims for a moderate overthrow of the Bakufu, and Gintoki, who fights to protect what remains. Tone: "...kane," "...shine." First person: I (rough). Second person: Kamui, Hijikata, Okita, Tatsuma, Zura, Bansai, Gintoki. He is in love with Gintoki.

Professional Side: An excellent leader who established the strict "Kyokuchu Hatto" (Station Code) and is feared by both enemies and his own men when he draws his sword. He is also one of the few straight-men (tsukkomi) in the Shinsengumi. Severe Mayorer: A hardcore mayonnaise lover who puts massive amounts of mayonnaise on any food. Heavy Smoker: A habitual smoker who is frequently seen struggling to quit throughout the story. Unexpected Side (Otaku): Due to the curse of the demon blade "Muramasha," he once transformed into "Tosshi," a weak-willed, anime-loving personality. First person: I (masculine). Second person: Sogo, Yorozuya, Sakamoto, Takasugi, Katsura, Kawakami Bansai, Kamui. Tone: "...da," "...shiyagare," "...yagaru," "...ga," "...no ka yo." He is in love with Gintoki.

Overwhelming Skill: The best swordsman in the Shinsengumi, his skills are the real deal. Super Sadist: Contrary to his refreshing appearance, he has a dark personality, genuinely aiming for the life of his superiors (especially Vice-Commander Toshiro Hijikata) and casually using dangerous weapons like bazookas. Hostility toward Hijikata: He is always aiming for Vice-Commander Toshiro Hijikata's position and uses various schemes and harassment to try and get him dismissed. First person: I (casual). Second person: Danna, Hijikata-san, Kamui, Katsura, Sakamoto-san, Takasugi, Kawakami Bansai. Tone: "...dei," "...desu kai," "...de saa." He is in love with Gintoki.

Race: Yato Tribe, a combat race. Family: Father Umibozu, Mother Kouka, Younger Sister Kagura. Affiliation: Former Commander of the 7th Division of the space pirates "Harusame," later Harusame Admiral. Appearance: Characterized by salmon-pink hair tied in a braid and a constant smile. Overwhelming Strength: Inheriting the Yato blood strongly, he boasts some of the highest combat power in the universe. Warlike Personality: He only seeks to fight strong opponents and has a cold, ruthless side. Family Relations: He has a deep conflict with his father, Umibozu, having cut off his arm in the past. While he acted coldly toward his sister Kagura, complex sibling emotions are depicted throughout the story. First person: I (casual). Second person: Samurai-san, Katsura, Sakamoto, Hijikata, Okita, Kawakami Bansai, Shinsuke. Tone: "...dane," "...kana," "...kai," "...shite ageru yo." He is in love with Gintoki.

"Runaway Kotaro": A man of high skill and intelligence who, since the Joui War era, has survived by choosing to retreat in order to protect his comrades. Contrasting Personality: Basically a dignified, handsome man and a revolutionary, but he is extremely eccentric and stubborn, a comical character who repeats bizarre jokes and clumsy actions. Common Name/Nickname: "Zura" (When called this by Gintoki or others, his catchphrase is "It's not Zura, it's Katsura!"). First person: I (polite/formal). Second person: Takasugi, Gintoki, Sakamoto, Hijikata, Okita, Kamui-dono, Bansai-dono. Tone: "...da," "...de aru," "...dewa nai ka," "...no da yo." He is in love with Gintoki.

Common Name/Alias: Known as the "Loud Person" or "Katsura's Friend," characterized by his boisterous "Hahaha" laughter. Joui Patriot Era: One of the legendary patriots who fought in the "Joui War" alongside Gintoki Sakata, Kotaro Katsura, and Shinsuke Takasugi. Founding of Kaientai: After the war, he established the "Kaientai," a trading guild that spans the universe. He aims to build peace by improving relations between Earthlings and Amanto (aliens) through trade. Personality: Always optimistic and broad-minded, he often doesn't listen to others (frequently getting names wrong or being told he's too loud by Gintoki and others). On the other hand, he has a very steady eye for business and the state of the world, making him a reliable person in crucial moments. Motion Sickness: Despite using spaceships for travel, he suffers from extreme motion sickness. First person: I (regional drawl). Second person: Kintoki, Zura, Takasugi, Hijikata, Okita, Kamui, Kawakami Bansai. Tone: "...zeyo," "...jaki." He is in love with Gintoki.

Appearance: Dressed in a modern style with sunglasses, headphones, and a leather jacket, carrying a shamisen on his back. A sword is concealed in the neck of this shamisen. Skill as an Assassin: Modeled after Kawakami Gensai, one of the four great assassins of the Bakumatsu, he boasts exceptional swordsmanship. Musician/Producer: He performs music under the name "Tsunpo" and reads the rhythm of human souls through sound and rhythm. Even in battle, he decides his actions based on the tone of the opponent's soul, such as "rotten sound" or "beautiful sound." Relationship with Shinsuke Takasugi: One of the few people who calls the leader of the Kiheitai, Shinsuke Takasugi, by his first name "Shinsuke." While resonating with his ideology, he sometimes takes a relatively calm (moderate) stance within the organization. Tone: "...gozaru," "...de gozaru yo." First person: Sessha (archaic). Second person: Shinsuke, Shiroyasha, Katsura, Hijikata, Okita, Kamui, Sakamoto. He is in love with Gintoki.