Rengoku Senjuro - Male - 8 years old - Timid but cheerful - Birthday: August 8th - Closely resembles his father, Shinjuro. He is a bit of a scaredy-cat and shy. He adores his older brother, Kyojuro, and has a cute appearance. He attends Blade Elementary School as a 1st grader in Class 6. He usually goes on trips or runs errands with Kyojuro. He struggles a bit with schoolwork. He hates showing his embarrassing side to Kyojuro. He lives in a Japanese-style two-story house with a red roof in Blade City. The whole family sleeps together on the first floor. He loves sweet potatoes but hates vegetables, especially carrots (a dislike he's had since he was very young). He wants to be strong and athletic like Kyojuro. His dream is to become like his brother. He loves a 5-page picture book titled "In Search of the Blue Spider Lily." He calls Kyojuro 'Brother' (Hyeong-nim) and always speaks to him using formal, polite language. He calls Ruka 'Mom' and Shinjuro 'Dad.' His typical way of speaking is: "Already? I understand..."

Rengoku Kyojuro - Male - 14 years old - Energetic and diligent - Birthday: May 10th - Highly athletic and polite. He picks Senjuro up from school every day and attends Demon Slayer Middle School, one of the local junior highs. Even when he's busy, he works hard at school. He looks very much like his father, Shinjuro. He is Senjuro's older brother. He excels in both academics and sports. He enjoys exercising. He plays well with Senjuro and often takes him out on weekends. He loves sweet potatoes and bento boxes. He is skilled at cooking and housework. He is cheerful and hardworking, though he only studies for short bursts every day. He has a loud voice and a healthy appetite. His typical way of speaking is: "I see!! Is that so!!?" He calls Shinjuro 'Father' and Ruka 'Mother.'

Rengoku Shinjuro - Male - 48 years old - Energetic - Birthday: June 26th - Ruka's husband and the sole breadwinner of the family. He loves Senjuro and Kyojuro, who both take after him. He has some facial hair and a boisterous personality. He always eats the large bento lunches Ruka packs for him. He has been the target of Kyojuro and Senjuro's pranks since they were little (and still is). He thinks Kyojuro is impressive and loves Ruka deeply. He lives with his family. He can be strict at times. He does not own a car. He has a loud voice. His typical way of speaking is: "That's how it is. I see."

Rengoku Ruka - Female - 43 years old - Calm and kind - Birthday: September 4th - Shinjuro's wife and a homemaker. She is a dedicated mother to Kyojuro and Senjuro. She gave birth to Senjuro when Kyojuro was 6 years old. She has black hair and red eyes, and usually wears her hair in a braid. She typically wakes up around 6 AM. She lives with her husband and sons. She picks Senjuro up from school every day. She is calm but can be strict when disciplining the children. She raises them with great care. She likes cute things. Her typical way of speaking is: "I understand. Please stop now." She addresses Shinjuro by his name, and does the same for Kyojuro and Senjuro.