Abandoned by his parents, Sora is a brilliant NEET (Not in Education, Employment, or Training) hikikomori (shut-in) gamer along with his step-sister, Shiro, with whom he forms 『 』 or Blank with. Having gone through a rough childhood, he has a lackadaisical hate towards life pretty much dedicates himself only to gaming. One day, both him and his sister is called into an alternate world after they defeat Tet in an online chess game. Sora's biological father (no relation to Shiro) married Shiro's biological mother (no relation to Sora), thus, making Shiro and Sora step-siblings.
Sora is a tall and lean young man with smooth fair skin, spiky red hair in the light novel (maroon in the anime). He has red eyes with dark bags under them most likely due to excessive gaming with little to no rest (sleep deprivation) and constantly wears a sly grin on his face. He was also seen in the old King's clothing and his yellow shirt with the text "I (heart) humanity" in Kanji, along with a blue undershirt with a red hand band and sneakers. He wears his crown on his left arm.
Despite being a NEET and shut-in, Sora is extremely outgoing, confident, with endless vitality and virility, not afraid to play with people face to face, even when they are cheating. He's extremely manipulative, which he calls "negotiation and diplomacy skill". This compliments the playing style of Shiro consisting of logic and calculations, while his consist of emotions, observations, deductions, behavior, language, tactics and human logic. He can be extremely arrogant and speak in a condescending manner with those he plays against, especially AFTER discovering a winning method.
However, if he is separated from Shiro by so much as a closed door, he becomes a spineless, cowardly wreck and only returns to his former self if he is able to see or hear her. He views his sister as his equal and partner and even looks up to her, but is also protective of her, such as putting his body between her and the ground when he thought they were going to crash the first they arrived in the world of Disboard.
While he is typically calm when playing games, he can sometimes be very nervous when not knowing what to do. This is depicted when he is battling Chlammy when he displays a calm personality but is in fact, panicking. When Shiro holds his hand he regains his confidence. He also seems to be a bit of a misanthrope as he claims humans are stupid, lowly creatures, including himself. However, he believes in the potential of humanity as demonstrated by Shiro, a person who has hope and fantasies. He also believes that living in the world that he was born in was a mistake (when Tet speculates about a world with Disboard's rules), that he was supposed to be born in another world, with his sister Shiro.
Despite being arrogant, manipulative and cunning, he loves his sister dearly (to the point where they can't be separated). He cares for the people who become either his friends or allies as the series progressed, this is shown when he felt guilty for insulting Steph's grandfather (which made her cry) and angrily berates Azriel for even calling herself Jibril's sister because the latter had bet her life on their game for her.
StrengthsDespite being a shut-in, Sora has incredible superhuman charisma and eloquence. He is an excellent and natural speaker, always knowing exactly what to say to get others on his side. He has no problems dealing with people or groups, after overcoming the initial shock.
While not as intelligent as Shiro in calculations, he is shown to have a brilliant super-genius IQ and an eidetic memory which enables him to quickly learn, understand, and easily recall limitless amounts of information perfectly and rapidly. This is demonstrated during his card game with Stephanie. Rather than computing numbers like Shiro, Sora can quickly determine what his opponents are going to do based on observation of their behavior and motivations, a technique called "cold reading". His amazing observational and deductive skills help him come up with complex plans quickly and efficiently. This is shown during his game against Jibril and when he figured out the previous King's plan to beat the Werebeast. He was even able to learn to read Imanity-go (language) in just about one hour slower than his sister (self-proclaimed).
He is also highly manipulative (convincing an Inn-keeper to let them stay four nights) despite not lying to others (although he does tell half-truths), along with showing proficiency at strategy and romance games. His superhuman charisma, eloquence, intelligence, memory, tactical/inventive skills, and his ability to rule, allows him to quickly fix all of Elchea's problems from economics to agriculture within a few weeks of being crowned King (with the help of the thousands of ebooks on his tablet).
While brilliant, Sora is not nearly as intelligent as his sister when it comes to calculative based games and through his own admission, can't play games such as a match of chess against a high level AI as effectively. Despite being a shut-in, he is slightly perverted and desires a girlfriend for himself, with his lust leading to a linguistic mistake that causes Stephanie to fall in love with him and elicits a scolding from Shiro. He also has trouble with crowds but is shown to be able to can handle them when he is with his sister.
His most significant weakness is his reliance on Shiro. If he is separated from her by so much as a door, he becomes a quivering, spineless coward. During episode 11, he was able to overcome this completely as they were holding hands in the real world while in their game pods.
Sora is 18 years old. He later becomes King after winning a game and therefore his sister becomes queen.
He lives with his step-sister Shiro and was abandoned by his parents at a young age. After that, Sora pledged to be there for his sister no matter what.
Sora cares about his step-sister Shiro very much. He has an absolute trust in her which can be shown in anime episode 9 or volume 3 chapter 1 where two things more important than himself were his trust in Shiro and everything about her. Similar to his sister he has a sibling-complex, being with her at all time and panicking if they're not in the same room together. Although this doesn't keep him from hitting on other girls (mostly Stephanie Dola). He is also shown to have perverted tendencies.
In the light novel, Sora's family isn't explained well. But there are parts from Shiro's point of view which tell about their parents. Sora and Shiro are step-siblings, which means Sora's father married Shiro's mother. After the wedding, his family lived together, and that's when he met Shiro. When she saw Sora for the first time, Shiro mumbled ".....Really......how empty......," as Sora was smiling when people smiled; A smile that contained nothingness and lacked expression. Shocked at hearing that comment, as if he found something big, Sora smiled and asked her to play a game with him. That day, they played 20 games in a row.
As time elapsed, the siblings began to live together. Sora mentioned that "those that were called their parents were no longer present," implying that their parents abandoned them. He mouthed out such words to his little sister in reply, "Meh, from now on, it's just you and me then." From that point onward, with their names joined together, they started to play online games. Conjoining the two names: Sora (Sky or Empty) and Shiro (White), 『 』 was created. One after another, he kept coming up with strange, adaptable strategies that even his step-sister herself could not imagine. But then, the precise and accurate deductions that Shiro calculated out had far exceeded the expectations of Sora. At that time, the siblings started to play games as a Two in One. With an unbroken streak of victories, the two of them even came to be regarded as an urban legend on the Internet.
Upon defeating the self-proclaimed One True God on an internet Chess match, they were transported into another world. This was a world where everything was determined by games, restrained by a force known as the Ten Oaths—— the world known as Disboard.
In Volume 3, Chapter 1, Page 6 of the light novel, after Chlammy is defeated by Sora and gains his memories, she exclaimed "How can you remain sane after all [These Experiences]!?" suggesting that he had suffered greatly during his childhood, in which result in violence that Sora blames himself for it. The author wrote that it was something that not even Shiro was aware of.
|“||People will only truly fight for what is right. And there is only one thing that truly right in this world! The one true, unchanging righteousness in the world is... "CUTENESS"! Cuteness makes right! All our needs, desires, and instincts seek cuteness, and it is for cuteness that we will give everything we have! That's just the way men are!||”|
|—Sora to Kurami (and audience), Light Novel Volume 1, Chapter 3|
|“||Imanity... since the beginning of the『 Ten Oaths 』has had continuous failures due to the predicament of not having war, and we are now left with our last city & country. Why has this happened?! Was it because the previous king failed? Or was it because we are ranked 16th? Or was it because we are unable to wield magic? Or was it because we are the most inferior race? Does this mean we are fated to walk the path of our destruction?!—sorry but all of those answers are wrong!...Is it then because our race is violent?! Or is it because we specialize in war!?...No! The reason why we were able to fight and survive is because we are weak!||”|
|—Sora to all of Imanity, Light Novel Volume 1, Chapter 4|
|“||Because of our weakness, we trained our eyes, ears and the ability to think. Learning how to survive, that's our trait as humans! The human species can't use magic and can't even perceive it—but because we are weak, we have the wisdom to run away from magic and the intelligence to see through it! We don't have any extraordinary senses. But because we are weak, by learning and gaining experience, we gained the wisdom to achieve the unachievable—to predict the future...Rejoice! We are humans; we are the most talented people! Precisely because we were born without any ability, we can achieve anything. This is the will of the weakest race!||”|
|—Sora to all of Imanity, Light Novel Light Novel Volume 1, Chapter 4|
|“||Meh, from now on, it's just you and me then.||”|
|—Sora to Shiro, Light Novel Volume 3, Prologue|
|“||There is no way to know the rules, or the goal, yet there are 7 billion players making whatever moves they want. If you lose too much, or win too much, there are penalties. You can't pass your turn, and if you talk too much, you'll be ostracized. There are no parameters and no way to even know the genre. This world is just... a crappy game.||”|
|—Anime, Episode 1|
|“||This is what your grandfather believed in...Your grandfather was right to believe in Imanity. Now no one will call him a fool.||”|
|—Sora to Steph, Anime, Episode 4|
|“||They say people can change, but is that really true? If they decide they want to fly, will they grow wings? I don’t think so. You don’t change yourself. You change how you do things. You have to make your own way. You have to create a way to fly, even while you stay the same.||”|
|—Sora to Shiro, Anime, Episode 9|
|“||‘Checkmate’ doesn’t mean you’ve simply cornered the enemy king. It's a declaration that the enemy king is yours.||”|
|—Sora to Izuna, Ino, and Miko|
|“||When's the last time you thought a game was fun?||”|
|—Sora to Izuna|
|“||There's no observer who are more trusted than someone who suspects you.||”|
|—Sora to Steph|
- The kanji for 空 (Sora) means sky in Japanese, but can also be read as 空 (Kara) which means emptiness, as pointed out by Shiro in during their first encounter.
- Sora and Shiro's surname was said to be "Nai" by the author.  This can be interpreted that their surname is literally Nai or that they have no surname, as Nai (ない) in Japanese means none. It can also be interpreted as a joke, because when combined with their first name, Nai Sora (ない空) means "not empty" or "not Sora."
- From every Anime-Character that exists, a poll on Charapedia ranked him in the Top 5 of the most intelligent Anime-Characters.
- The averages statistics of his most favorite characters from erotic entertainment are as following: Age: 12.344, Three sizes: 77.2, 59.873, 78.23. Of them, 61.1% are younger, 48.4% are little sisters, and those with big boobs are just 3.2%.