Chapter 263, "An Uninvited Guest", is the clearest early answer because it turns Mount Shu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with At the entrance to Mount Shu, two streaks of light descended, and a... and follows through with How many fragments are needed to forge a complete human race Ultimate....

It could be a mysterious figure from another dimension. In a more fantastical version of the story, this uninvited guest could be a being that has accidentally slipped through a portal during the game. They have no idea about the world they've entered or the rules of the game, but their presence causes all sorts of strange things to happen.
Chapter 661 is the strongest chapter-level answer because it starts from A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,... and follows through on To his right was a security guard, sound asleep, and to his left was Mu....
Chapter 661 is the strongest chapter-level answer because it starts from A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,... and follows through on To his right was a security guard, sound asleep, and to his left was Mu....
Chapter 661 is the strongest chapter-level answer because it starts from A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,... and follows through on To his right was a security guard, sound asleep, and to his left was Mu....
Chapter 661 is the strongest chapter-level answer because it starts from A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,... and follows through on To his right was a security guard, sound asleep, and to his left was Mu....
A practical answer is Chapter 661, because it turns the idea into a concrete scene. The chapter opens with A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,..., adds pressure through You're overpraising me, Miss Jiang....." "Psh, a little thing like this,..., and ends on.
A practical answer is Chapter 661, because it turns the idea into a concrete scene. The chapter opens with A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,..., adds pressure through You're overpraising me, Miss Jiang....." "Psh, a little thing like this,..., and ends on.
A practical answer is Chapter 661, because it turns the idea into a concrete scene. The chapter opens with A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,..., adds pressure through You're overpraising me, Miss Jiang....." "Psh, a little thing like this,..., and ends on.
A practical answer is Chapter 661, because it turns the idea into a concrete scene. The chapter opens with A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,..., adds pressure through You're overpraising me, Miss Jiang....." "Psh, a little thing like this,..., and ends on.
A practical answer is Chapter 661, because it turns the idea into a concrete scene. The chapter opens with A moment later, Zhuola let out a cold laugh, her voice hoarse as she said,..., adds pressure through You're overpraising me, Miss Jiang....." "Psh, a little thing like this,..., and ends on.