Twin Souls in the Apocalypse

[Not a conventional apocalypse story. Do not apply the worldview of other settings.] [The first ten chapters are setup. If you want to get straight to the apocalypse, skip to Chapter 11.] [Apocalypse + two souls in one body (high IQ) + a touch of ensemble cast and multiple viewpoints + character growth early on, satisfying payback later + no male lead] You know about dissociative identity disorder, where one person has two different personalities. That is what Feng Yuke tells people: she has another personality named Feng Yuai. But only the two of them know that this is not actually two personalities. They are two souls in one body. No, now they are not the only ones who know. One night, a god visits them in a dream and tells them the apocalypse is coming. If they do not intervene, the world will reach its end. At first they do not believe it. Then they think the third great species explosion must be the apocalypse in question. But then supernatural abilities appear, along with a voice-wielding witch, dream-invading spirit devourers, and a maddened World Tree... Is this what the apocalypse really is?