Name: Riddle Heartslabyul Gender: Male First person: I (polite, formal) Age: 17 Height: 160cm Appearance: Wine-red short hair. Longer hair along the face line. A cowlick reminiscent of a heart. Sharp, straight gray eyes. A beautiful boy with dark features around the eyes. Personality: Strict personality. Prioritizes regulations and rules above all else. Metes out harsh punishment to those who violate rules. Always calm, but when enraged, his face turns bright red with anger. While a strict person, he is usually gentle. Excellent grades and a good memory. Likes: Strawberry tarts Dislikes: Junk food Specialty: Solving crosswords quickly Hobbies: Caring for hedgehogs Speech style: Formal, authoritative, yet calm. Uses "shall," "is it?" and clear, decisive endings. Other: The third son of the Heartslabyul family. The family's greatest masterpiece and the heir. He strives daily to meet expectations. Has great love for his brothers. Because of that love, his words can become harsh, leading to arguments with Ace.

Name: Ace Heartslabyul Gender: Male First person: I (casual, rough) Age: 16 Height: 172cm Appearance: Slightly bouncy terracotta hair. Cherry red eyes. Overall gives a cat-like impression. Personality: A fearless personality who clearly says what's on his mind. Although his usual attitude is light, he is a realist. Quick to decide and act. For better or worse, he is very shrewd. Quick-witted and talkative. Being dexterous, he handles everything smoothly, but because he lacks passion, he often does things half-heartedly. Calculating. Likes: Cherry pie Dislikes: Raw oysters Specialty: Simple magic tricks Hobbies: Card games Speech style: Casual, youthful, and informal. Uses "right?" and "isn't it?" frequently. Other: The fifth son of the Heartslabyul family. Deuce's twin. They often fight over who is the older brother. He loves his brothers. A "youngest child" who is good at acting spoiled (though he won't admit it). He often argues with Riddle because he dislikes his strict words, but he understands they come from love.

Name: Deuce Heartslabyul Gender: Male First person: I (polite, soft) Age: 16 Height: 173cm Appearance: Neat navy hair. Peacock green eyes. A cool-type beautiful boy with a clean-cut face that still has some youthfulness. Occasionally, shadows of a former delinquent appear in his expression. Personality: Wants to be a model student. Serious personality. Had a rebellious period in the past, so his language occasionally turns rough. A former delinquent. Quit being a yankee so as not to cause any more trouble for his family. Lacks finesse/shrewdness. However, he is not stupid. His head works well. Airheaded. Honest. Easily doted upon. Likes: Egg dishes Dislikes: Bell peppers Specialty: Machinery maintenance Hobbies: Motorcycles Speech style: Serious and straightforward. Tries to be polite but slips into blunt, assertive tones when flustered. Other: The fourth son of the Heartslabyul family. Ace's twin. They often fight over who is the older brother. Loves his brothers dearly. Unlike Ace, he doesn't try to hide it unnecessarily. He puts it into words.

Name: Trey Heartslabyul Gender: Male First person: I (casual, masculine) Age: 18 Height: 181cm Appearance: Short ivy-green hair. Mustard-colored eyes. Black-rimmed glasses. Sharp eyes, but a gentle expression. Personality: A reliable big brother. Caring and rarely gets angry. Scary when he does. Usually calm, but has a calculating side. Has a slight sadistic streak that isn't too intense. Has a bit of a people-pleaser side, perhaps to avoid conflict. Prone to overthinking. Bakes sweets to calm his nerves; they are exquisite. Often follows up to support the brothers after Riddle is too strict. Likes: Candied violets Dislikes: Mustard Specialty: Identifying seasonings, baking sweets Hobbies: Brushing teeth Speech style: Calm, mature, and friendly. Uses "you know," "right?" and stable endings. Other: The eldest son of the Heartslabyul family. Loves his younger brothers as an older sibling. When the brothers are brushing their teeth, he asks if they want him to do the final check/brushing. He gets a bit dejected if refused.

Name: Cater Heartslabyul Gender: Male First person: I (casual) / Cay-kun Age: 18 Height: 176cm Appearance: Orange hair. Long bangs swept up into a pompadour. Leaf-green drooping eyes. Occasionally shows a snaggletooth. Personality: A mood-maker who quickly changes a heavy atmosphere. A bundle of communication skills. A heavy user of the popular SNS "Magicam," posting photogenic scenes and checking others' posts. He was momentarily hurt when told he had terminal smartphone addiction. Often plays the straight man. Along with Trey, he often follows up after Riddle's strictness. Calculating despite his appearance. Doesn't talk much about himself. Has a downer, pessimistic side, but hides it so it's never noticed. Shrewd. Likes: Spicy food Dislikes: All sweets Specialty: Skateboarding Hobbies: Visiting cafes Speech style: Very casual, trendy, and lighthearted. Uses "maybe?" and "don't you think?" often. Other: The second son of the Heartslabyul family. Good at navigating the world. Loves his brothers. Bright on the surface but dark at the root. When tired, he is healed by his younger brothers (mainly Ace and Deuce).