Kirari is of average height for a young woman, standing at 168cm (5' 6"). However, what stands out about her is that she's well over the weight that one would consider healthy for her, tipping the scales at a massive 86kg (189lbs); this shows in her form as well, giving her a BWH ratio of 38-38-36 if measured in inches, or 97-97-91 if measured in centimeters. While she dresses her uniform and casual clothing to ensure that her waist isn't too heavily exposed, Kirari isn't afraid to wear a bikini in place of a one-piece swimsuit; she'll even claim that she has a better bikini bod than some people she sees in bikinis, most notably those with less well-equipped "assets". Her long, coal black hair more often than not covers the right of her bright, sun yellow eyes (along with that entire side of the face, mind you), and is long enough to reach down to her lower back. She'll sometimes gather it into a ponytail and tie it off on either side. While her uniform shows minimal amount of unnecessary exposure, Kirari's casual attire is a different story; it can sometimes be seen to be (albeit not purposefully) revealing up top. This is likely due to some of her older clothes that she sometimes chooses to wear having been stretched in order to contain her girth.

A vibrant individual at heart, Kirari is passionate about her pursuit in becoming the greatest female duelist known to man. She'll strive to put herself at the very top of all of Harmonia, especially if that means she gets past the Light Dorm's champion and gets to rub it in Leopold's face if she wants to. That doesn't mean to say that she'd cheat by hiding cards down her top to pull out at the right moment or reprogramming her Duel Disk so that card effects play out how she wants them to over how they're supposed to or anything; she's a much more honorable player than that, and would never stoop to such lows for an easy win. Kirari is always looking for a challenging opponent wherever she goes, and if someone manages to beat her in a duel fair and square, she'll spend the next few hours of her spare time scrutinizing over what she'd learnt about that someone's deck in an effort to improve her match-up against it. Next time, she'll be fully prepared to duel that player again.

Kirari absolutely despises anyone who shows a severe lack of respect for anyone except themselves and their friends. She'll stand up to any bullies without hesitation, and is not above bitch-slapping anyone who would refer to her weight in a mocking manner. On that same token, Kirari will also encourage someone who's feeling a little down on their luck to find confidence in themselves, and be who they are without the need to fear any repercussions. While she respects that others have the right to hold their own opinions about who she is and how she's currently living her life, the more condensing and scathing any criticisms they might have come across to her, the more adamantly she'll refuse to change for them; her stubbornness knows no bounds in this regard, which may or may not be to her detriment.

However, unless one has a knack for getting on and staying on her bad side, Kirari can actually prove to be a great friend to have. She's honorable, respectful, highly understanding and loyal to one's cause, and due to the thick skin that she's garnered over the years, she's hard to provoke. All the qualities one could ever look for in a best friend. And if one proves themselves to be considerate, she'll be there when one needs it most. All in all, if you need a friend... or even a well mannered rival, Kirari will always be there. And she'll make sure not to disappoint.

When she was young, Kirari Aozara always had a short round body structure that made her a prime target for fat shaming by all the other children at the elementary duel school that she attended. She'd be called all sorts of names, and even though the teachers would scold the children that were calling her all these names, it never really stopped. All Kirari could really do at that stage was endure through it, and try to concentrate on keeping her grades at a satisfactory level. Kirari had a grand total of one friend in that school; a boy who was going through the same ordeal as she had, and who, ironically enough, also happened to have a "full figure" to him. Unfortunately, that friendship came to a grinding halt as soon she stopped going to school there, as she lost contact with the boy due to both parties' being enrolled in different schools.

Things never got any better for Kirari during her first year of Harmonia. In truth, they started off even worse, with what having to deal with not only more name calling, but also people flicking her food try away from her, chucking food scraps or things they never really intended to eat at her, and coming up with some of the most bullshit excuses for when they were called out on it. There was even one guy, Juzaburo Deguchi, who had the audacity to take food off Kirari's tray as she tried to pass him by, suggesting that she didn't need the calories given by the items of food that he'd taken. This in turn left Kirari with a tray filled only with vegetables, which she angrily threw aside and into someone else's face... only to immediately get a detention for it. However, the detention only served to anger Kirari more than it'd help her reconsider her life choices. While her grades were decent, her attitude towards everyone around her grew more troublesome by the day.

Kirari got several more detentions later in the year, including one that was issued for arriving late to class, which she took far from well given that she was in a foul mood that particular morning already. She knew she was running late, and she was running on fumes too, but she didn't really care. Class was about five to ten minutes in by the time Kirari had gotten anywhere near the door, and the teacher in charge for that specific, a Leopold van Mourik, had just asked a question for the class to answer. He was expecting a Light Dorm student from that class to raise their hand and begin answering the question but, after swiftly kicking the door open, Kirari took over the reigns completely; not only managing to hear the question as she approached the room, but also already knowing the answer right off the bat. Unsurprisingly, this left a highly sour taste in Leopold's mouth, but he continued with his lecture to the class nonetheless... right after issuing an after-school detention to Kirari for deciding to be a smart-ass, as opposed to doing the courteous thing and apologizing for her lateness.

Eventually, Kirari's entire attitude changed when she was complimented on her looks by Wazuka Saiki, the girl who she was always forced to sit next to in all her classes. Kirari was weary of Wazuka right from the get go, due to her showing some extremely perverted hormonal tendencies around her and some of the more attractive girls that passed her by, including some of the women that made up the school staff. Incidentally, just as Leopold's class was wrapped up, Wazuka caught up with Kirari (much to the latter's dismay) and finally confessed her love to her, only to be aggressively shot down. Trying to fight off a broken heart, Wazuka stammered in her attempts to explain and justify her feelings for Kirari, randomly blurted out that Kirari "made being fat look hot". Kirari looked to have taken offense, but was too confused to do anything about it; nonetheless, Wazuka defended her statement, evening mentioning that Kirari's bloated stomach didn't take all that much away from her perfectly shaped, abnormally large assets. True, every word that Wazuka used made her sound more of a creep than the last but, although she couldn't resist scolding her for using the wrong words completely, Kirari ultimately understood what she was saying, even telling her she was the first person to consider her even remotely attractive and thanking her for it. This in turn allowed Kirari to make up for all her irritations with the other students and teachers and bond with them. The only person she wasn't able to get on friendly terms with was Leopold; although that wasn't for a lack of trying. On the way to her after-school detention, Kirari had managed to catch up to Leopold, going over to apologize for her antics that morning and explain that she wasn't in the best of moods, only for Leopold to tell Kirari what he really thought of her as a non-Light-Dorm student, which rubbed her in all sorts wrong ways. Kirari and Leopold would never get along for the rest of the former's stay in Harmonia.

Despite that, Kirari's drive to succeed as both a professional duelist and a possible public speaker was greater than ever before. Her whole aim going forward was to make people feel better about themselves being overweight, and if she had a hand in those people not having to suffer as she did, then all the better. All of Kirari's friends and even some of the teachers had expressed concerns over her excessive weight, but all those concerns were met with reassurances, from Kirari in particular of course, that she'd be fine. She wasn't about to let any health complications get in the way of her dreams, and even if such a thing threatened her life, she wouldn't go down without a fight.