『 』 (空白, Kūhaku, lit. "blank") is the online game username and account shared by Sora (空) and Shiro (白). It has become an urban legend in the real world for holding the top score of over 280 games without having any recorded losses or defeats. After Sora and Shiro were called to Disboard by Tet, they used the name to refer to themselves, and the urban legend became a legend.
『 』 is generally depicted by four game accounts, the main account being named 『 』, and the others named 『 SUB01 』, 『 SUB02 』, and 『 SUB03 』, with Sora and Shiro controlling two accounts each.
While never losing, they technically lost to Jibril during the game with the Old Deus Holou. Although, this is unknown if this can be counted as a "loss." On a technical level, they did lose. However, its speculated its much like chess where in order to win, some chess pieces must be lost, but does this technically mean they lost? It is considered by Jibril, Sora, and Shiro that it was a draw (due to running the time limit) but this is Blanks "First ever real loss" as said by Sora. While unknown if Sora meant it literally, or as if it was a chess piece, he does state that "We were up against an Old Deus, i didn't expect it all go according to plan" leading to a possibility that he regards it as a moral loss due to the circumstances about Jibril commiting suicide.
Extreme Intellect: While both siblings are incredibly smart, Shiro is respectively the one who acts more as a super-computer in a sort of way. For an eleven year old, her understanding of mathematics and calculations in general is superior to her brother. She uses this advantage greatly in games as shown when she accurately calculates how to shoot her bullets as to deflect her opponent's bullets. Shiro was able to learn the entire language used by Imanity in less than twenty minutes claiming her brother was just "slow."
Charisma: This skill being possessed by Sora more so than Shiro, when push comes to shove Sora is able to convince anyone to see his side and effectively win over the general public.