Ritsu Sakuma

Though he may seem cold and uninterested, Ritsu is a playful and intelligent person at his core. Energy isn't something that comes naturally to him, and he is instead quietly passionate, and likes to tease others, enjoying their reactions.

At the start of the year, Ritsu tended to distance himself from his classmates and idol activities, which he viewed as laborious and boring because of the previous fractured state of Knights. He was reluctant to make friends due to this, and clung only to his childhood friend, Mao, who worried over Ritsu's antisocial nature. However, as the year goes on, Ritsu begins to open up and form important bonds with his friends and unitmates. He is very loyal and affectionate to the select few he is truly comfortable with.

Ritsu can be blunt and harsh to a fault, but is very intuitive and often picks up on others' emotions. He regards psychoanalysis as a 'bad habit' of his, yet is very adept at it. At times, he can be very clingy, and loves it when others praise him. He can be violent, especially towards his older brother, and doesn't hold his tongue often. Despite this, he can get very protective of his loved ones, to the point of being possessive, as seen with his interactions with Mao, though he gets better at learning to rein in his jealousy later on.

Ritsu has abandonment issues largely stemming from Rei's absence last year, which contributes to his clingy and possessive tendencies, yet also his habit of distancing himself from others as a whole. He shares Rei's aversion of sunlight, and becomes more active and 'alive' at night. They also share a habit of jokingly regarding themselves as older and wiser than their juniors.

He loves music and is known for playing the piano. His songwriting reveals a much deeper and more wistful side of him, something that he almost never reveals to others, preferring his smug and sleepy persona. Somewhat surprisingly, though, he tends to keep things to himself to avoid burdening others.

Ritsu stands at average height with red eyes and a fair complexion. He has mid-length black hair with bangs and side bangs that frame his cheeks. He has a tiny speck of hair and a stray bang sticking out of his head. At school, he wears his school blazer unbuttoned over his gray sweater. His white shirt is untucked with a messy collar. He wears brown dress shoes and loose plaid pants.

On stage as a member of the unit Knights, Ritsu wears a dark blue coat with white sleeves and a ruffled tailcoat over a white shirt. There’s a vertical blue line on his sleeves. The sleeves have a blue cuff, with a gold accent to them. His white shirt has a black vertical line in the middle, accented with gold. His shirt collar is blue, accented with gold as well. On the shirt’s collar, there are swirly gold patterns. Where the buttons would usually be, are golden frog closures. On his jacket there are black epaulettes. The rope on the epaulettes are golden. From his left epaulette are two golden strings, which lead to a blue banner with the fleur de lis symbol on it which is pinned on the right side of his chest. On the back, he wears a cape which is blue on the top end and white on the underside. There is a golden accent on the blue half of the cape. His pants are dark gray, with light gray vertical lines on them. He wears a thick belt with four golden buttons on them. There are golden lines on the side of his belt. Attached to the belt are two golden ropes. His boots are white, with the tip and the bottom being black. There is a black vertical line going down the shoe, with gold shoelaces. Under the shoelace tie are two black belts with a straight vertical gold buckle. Ritsu wears black fingerless gloves.

Rei Sakuma: Ritsu is Rei's younger brother. They used to be close when they were children, with Rei taking on the role of Ritsu's primary caretaker. Their relationship took a sharp turn when Rei left overseas, leaving Ritsu alone at home feeling abandoned by his older brother. Ritsu now treats Rei with a cold distance or open disgust, and often refers to him as a stranger or an insect, while Rei longs to be closer to Ritsu again, much to the latter's revulsion. Whenever Rei sees Ritsu, he is quick to drop everything and tell his brother how cute he is, no matter what he was doing, with Ritsu pushing him away and even going so far as to tell him to die. Whenever Ritsu shows any indication of caring about his older brother, Rei is quick to gush about him "reverting to the 'old Ritsu'".[12]
Ritsu's dislike towards Rei is often expressed extremely harshly, such as when he declines the fact that he had a brother or threatens to kill him.

Eichi Tenshouin: They first met during the Checkmate Live. Eichi said that Ritsu's only worth was having Rei Sakuma as an older brother, to which Ritsu retaliated by hitting him.[1]
In Black Tea, it is revealed that they met again shortly after, when Eichi tripped over Ritsu on the ground. Eichi offered to help Ritsu to the infirmary, with the intention of bringing down Rei using his younger brother. Ritsu, immediately realizing his ploy, lied that his brother abuses him so Eichi can pity and spoil him. They started hanging out over tea, until Eichi realized months later that Ritsu had been messing with him. He confronted Ritsu, who readily admitted to tricking him. After this, Ritsu advised Eichi in his plans to take down Rei and together they established the Tea Club. As Eichi's plans progressed, he stopped confiding in Ritsu about them but still attended their Tea Club activities, becoming weaker over time until his collapse during a club meeting.
Eichi is grateful to Ritsu for protecting the Tea Club during his time in the hospital. The two tend to bicker over meaningless things, but are otherwise on good terms.
Mika Kagehira: Mika and Ritsu are classmates in 2-B who became friends due to their tendency to hide in the corner of class. When they first met, Mika expressed interest in Ritsu claiming to be a vampire, so Ritsu later brought him an old book from his home library to try translating. Mika noticed a tear in Ritsu's Knights uniform and fixed it for him. During Cheval Live, Ritsu notices Mika's stress and encourages him to reach out to others for help.
In their third year, Mika and Ritsu are no longer classmates, but they remain friends and practice together. After Neverland, Mika and Ritsu become dorm roommates. Mika was nervous about living with someone else at first, but he finds that living with Ritsu is easy because it's similar to when he had to take care of Shu. Ritsu is happy to have another person taking care of him. Ritsu often pranks Mika.

Mao Isara: Childhood friends and neighbors. Mao often takes care of Ritsu. Ritsu cares deeply about Mao and enjoys being spoiled by him. Ritsu has deep affection for Mao and considers him his family. When Ritsu was younger, Mao was one of his only friends, as Ritsu wasn't encouraged to get involved with anyone outside of his family due to his condition. To Ritsu, Mao was the person who gave him warmth and dragged him into the light after Rei began to leave him behind. Mao ensured Ritsu continued to attend school during that time.
They met for the They first met when they were in elementary school, after teachers from his Youth Group asked him to deliver a message to Rei in hopes for him to continue attending the group. Upon inviting Mao into their house, Mao was subject to a rubber band gun attack by a young Ritsu, hoping to kill him and get him away from his older brother. After hearing from Mao why he was sent, Rei figured it would be a good idea for Ritsu to join the Youth Group instead, and they became acquainted through their time in the Youth Group together. While they struggled to get along at first, Mao found Ritsu easy to work with as he found Ritsu to be a similar temperament to his younger sister; someone who acts like a spoiled princess who can be appeased by acting like a prince and doing whatever they say. Eventually their bond grew into a genuine and close friendship.[6] After having misheard is name the first time hearing it, Ritsu nicknamed Mao "Maa~kun", and Mao nicknamed Ritsu "Ricchan". However, as Mao grew older, he began to more often call Ritsu by his first name when talking to or about him, only calling him "Ricchan" very occasionally. Mao says that their fight in Band Ensemble was the first time they've ever fought.
Aware that he's unsociable and lacks the power to keep people he loves by his side, Ritsu clings to Mao, as he is the only friend he has (which he isn’t). Ritsu often playfully flirts with Mao, sometimes mao humors him.