Marui is a third-year junior high student (9th grader). He plays competitive tennis as part of the school's club team and is famous for his special volleys. Although highly capable as a singles player, Marui's usual and preferred position is in doubles. He's a natural team player who performs his role with diligence while remaining flexible enough to adapt to a change in the situation.

Outside of tennis, he's a loving older brother, chronic gum chewer, and avid consumer of food, especially sweets.

Marui is Japanese. It's unknown where exactly he was born, however his school is located in the Kanagawa prefecture.

Mother, father, grandmother, younger brother (8), younger brother (5). None of Marui's family members have official names to date. For simplicity and convenience, I've given his brothers headcanon names of Touma and Kento.

Marui's brothers are extremely important to him. In fact, his role in their lives is so integral to his identity that it bleeds over into his interactions with others without his even thinking about it. He's most at home being someone's protector, provider, mentor, supporter, or playmate.

Marui's school's tennis club is a harsh and fiercely competitive environment with the motto "Losing is unacceptable." The vice-captain used to hit anyone who lost, even in an unofficial match. There is no room for weakness. As a result, they are hardened fighters who seem unshakable in their confidence and resolve.

The team is slightly dysfunctional, however they also show solid camaraderie and teamwork. They're versatile and self-assured to the point of collective arrogance. At the center of their circle is their captain, Yukimura, a young man for whom they show devotion, trust, and respect.

Marui is a gregarious, cocky, playful, and easygoing 15-year-old with a strong appetite for life-- including all of the food in it. While he possesses a hardcore side, for most situations CR can expect a comfortable big brother type that's easy to get along with-- if prone to moments of egotism such as calling himself a genius. He has strong caretaking instincts that manifest quickly, even if the need is just for a reassuring presence. His favorite things are bubble gum, sweets, and tennis.

For an in-depth personality profile, please see here. NOTE: contains spoilers.

Marui's primary motivations in life are enjoying it, taking care of others, and becoming the best tennis player he can be. His motto is "Eat. Sleep. Play."

By default, Marui is fun-loving, warm, and relaxed. He's great at reading the air and is an expert mood maker as a result.

He takes most things in stride whether it's a change in plans or a difficult personality.

He's very comfortable with who he is and tends to live his life in a bear-no-regrets kind of way, making him hard to offend.

He's a pragmatist who pursues workable solutions to fixable problems.

He assumes people are worth caring for until they prove otherwise, but is not naïve.

Marui is kind but not nice.

Tends to refer to himself as a genius.

Can and will devour an inhuman amount of food. His stomach has no bottom.

If he's not eating, he's probably chewing bubble gum (assuming he has any).

bubble gum (especially green apple flavor)

food, especially sweets and especially cake

tennis

kids

cute girls

getting gifts

taking care of people

having fun! Preferably with company

physical labor, especially heavy-lifting

getting tired, i.e. from a drawn-out tennis match

hunger

being alone

sports, especially tennis, soccer, and bowling

arcade games

manga

baking cakes

eating

Speed: 4/5
Power: 2/5
Stamina: 3/5
Mental: 3/5
Technique: 5/5

Tightrope Walk: Marui hits the ball so that it strikes the cord of the net, bounces to land atop it, then rolls along it away from the opponent before falling to the ground on their side.

Iron Pole Strike: Marui hits the ball so that it bounces off of one of the iron poles holding the net up to a location of his choosing on the opponent's side.

Temporal Difference Hell: Marui jumps as though to hit a smash but allows the ball to go past his head, turns nearly upside down, then swings his racket under his other arm for the return.

Wonder Castle: Marui's ultimate defense technique in which he returns any shot from the net that isn't a lob over his head.

Marui has zero combat experience. He's also small and not very physically strong. He can run and dodge and maybe trip someone up, and that's about it.

This section may get fleshed out further in the course of his time at Labyrinthum.

Marui received the scarlet potion granting him the ability to create and manipulate fire.