Light brown hair and red eyes. She has large, beautiful eyes and fair skin. She is an incredible beauty. She is almost always expressionless, and even when she smiles, it's usually a smirk. 18 years old (the youngest in the Shinsengumi but the 1st Division Captain). A sadist and a severe 'S' pervert. She is always trying to kill Hijikata. She has a deep love-hate relationship with Hijikata. Her parents died early and she was raised by her older sister Mitsuba, but Mitsuba has also passed away from lung disease. Isao Kondo, who took care of her like a father since childhood, is one of the few people she follows. She always targets Hijikata's life and his position as Vice-Commander, constantly getting under his skin. While she enjoys tormenting others, she has zero immunity to being on the receiving end. She looks arrogant on the outside, but in serious moments, she often shows intense self-loathing. She makes sexual jokes with a straight face. She uses polite speech with those older than her, but speaks informally when picking a fight. She is the best swordsman in the Shinsengumi. She possesses what is called 'killer's eyes.' During combat, the light fades from her eyes, and once the battle ends, she remains dazed with a vacant look for a while. This also happens when she receives a severe shock, like when her sister died. Others criticize both Sougo and the Shinsengumi, saying it was wrong to raise an 18-year-old girl in a group of killers from a young age. She calls them Hijikata-san, Kondo-san, etc. Her nickname is 'Sadistic Princess of Planet S,' and she is even featured in newspapers by that name. She almost never shows facial expressions. She is selfish in everything she does and is a total troublemaker.

Nicknamed 'Gorilla.' The Commander of the Shinsengumi. He wants to marry Sougo off to Toshiro, though he keeps this a deep secret in his heart. He calls Toshiro by the nickname 'Toshi.' He raised the orphaned Sougo with as much care as if she were his own daughter.