Existence Othello

Also known as "Memory Stealing Othello*, is a special game of Othello which we will call Existence Othello because of the nature of the game which was played between Chlammy Zell and Sora in the 9th Episode, Sky Walk, of the No Game No Life anime series. It uses Othello stones to represent an aspect of the player and memories of that aspect and lose it when taken.

History
The game was a plot created by Sora in order to convince Chlammy to ally with him to conquer Eastern Union. Since the game takes away a certain aspect of the player's existence and is connected with the player's subconsciousness allowing Chlammy to see Sora's memories when the Othello stone is taken, Sora lost certain stones on purpose and lost his existence. However, he mentioned before the game, that the partners can participate in the game when a player cannot continue letting Shiro retain memory of Sora since she was technically part of the game. Meanwhile, Shiro still retaining memories of Sora convinced Jibril and Steph of Sora's existence. After, Steph slipped despite nothing on the floor, letting the group discover Othello stones on the ground. Despite Shiro not knowing the existence of the game before, realized Sora's plan and began to visualize the game how Sora had played in order to continue the game. This made 『　』 win and restore Sora's existence after the game has ended. The remaining stones that Shiro played represent three aspects of Sora which are:
 * 1) Everything that Shiro is
 * 2) Absolute faith in Shiro
 * 3) Ability to win games

The bet made in the game was for the victor to make 2 demands from the defeated where the first was Chlammy retaining the memories that they received while regaining their own, restoring Chlammy's awareness and consciousness. The second demand was for Fiel Nirvalen to report false information to the Elven High Council about Immanity's victory against the Werebeasts.

The game ended with Chlammy making an alliance with Sora, with both sides knowing their past experiences and future plans.

Rules
The rules are similar to Othello on the objectives on how to win by getting the most number of colors face up in the board. However, the stones represent a certain aspect of the person playing with the first stone being the most important according to the subconsciousness. When the opponent takes the piece, losing that part of the player's existence and the opponent attaining memory of that part of existence.

Trivia

 * The three unused stones were the first to third stones, which were the most important aspects to Sora.
 * The game occurred in the King's room hidden from reality using Fiel's magic which was detected by Jibril.