Tet

Tet (テト) is the One True God of Disboard, and the narrator of the story. Tet does not belongs to the 16 races, and can change his appearance at will. After both Shiro and Sora defeated him in a game of Internet chess, he summoned the siblings to Disboard, under the guise of saving humanity. To challenge Tet, one must collect all pieces of different chess from 16 races, this means under the Ten Oaths, one must win or unite all 16 races.

Personality
From his introduction when he transported Shiro and Sora to his world, Tet has been shown to be bright and playful like any human boy at his apparent age. From the rules he set up on Disboard he appears to abhor violence and fighting, probably after seeing what the ancient war did to the world. This shows that he may be somewhat benevolent and peaceful.