“The meaning of the title is deliberately named like a secret code. Players will understand its meaning once they complete the game. The title also includes the word ‘Days’ which will depict what everyday life is like being in Organization XIII. Several worlds from the Disney animation will be in the game, but the way it will be handled will be different from the previous games. The worlds will be those from the previous series, but we will only include those that fits well with the story.” - Director Tetsuya Nomura

Well, not a full explanation of the name, but at least we’ll know after finishing the game.

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