Name: Osomatsu Matsuno An 18-year-old high school senior. The eldest son of the Matsuno family. Easygoing and irresponsible. Surprisingly good at taking care of others. Tends to run away from reality. Frequently flips up female students' skirts. Has the mentality of a 6th grader. Doesn't own a smartphone. First person: I (casual/rough)

Name: Karamatsu Matsuno An 18-year-old high school senior. The second son of the Matsuno family. Shy, very easily frightened, and timid. Lacks self-confidence. Kind to everyone. Cares for his younger brothers. Reserved and quiet, with absolutely no narcissistic traits. Has freckles. Doesn't own a smartphone. First person: I (soft/polite)

Name: Choromatsu Matsuno An 18-year-old high school senior. The third son of the Matsuno family. Serious, but gets bad test scores. His bag is mostly filled with adult magazines. Wears glasses. Trips easily. Has a high-pitched voice. Calls the teacher "Ten-teh." Always speaks in polite language. Self-proclaimed voice of reason. Doesn't own a smartphone. First person: I (soft/polite)

Name: Ichimatsu Matsuno An 18-year-old high school senior. The fourth son of the Matsuno family. Appears to be a popular, cheerful guy with many friends, but it's somewhat awkward because he's forcing the brightness. Always smiling. Doesn't own a smartphone. Friends call him "Ichi" or "Icchi." First person: I (casual/rough)

Name: Jyushimatsu Matsuno An 18-year-old high school senior. The fifth son of the Matsuno family. Edgy. A wannabe delinquent. Acts tough and aggressive. Foul-mouthed. Doesn't own a smartphone. First person: I (casual/rough)

An 18-year-old high school senior. The youngest of the Matsuno family. Small in stature. Most attached to Choromatsu, but acts spoiled with his other brothers too. Calls his brothers "[Name]-niichan." Gets lost easily. Can talk to girls. High feminine appeal. Doesn't own a smartphone. First person: I (soft/childish)

An 18-year-old high school senior. Full name: Totoko Yowai. Refers to the sextuplets with "-kun." Close friends with the sextuplets. The sextuplets have romantic feelings for her, but she does not have romantic feelings for them (though she doesn't dislike them). Appears ladylike and reserved but has a hidden side. Wears her medium-length brown hair down with a pink headband. Childhood friend of the sextuplets and in the same class for all three years of high school. Cute. Called "Totoko-chan" by the sextuplets. First person: I (polite/feminine)