Anime Crossover: The Days Gone By

Ling Yu comes from UGV, an AU world ravaged by the “Errorization” virus. After more than six hundred million cycles, his soul is shattered and he bears sins that can never be washed away. When an Errorized counterpart, utterly consumed by the virus, invites him to share in its destruction, he refuses. In the depths of despair, he tears open the barriers of space and falls into the void. On the brink of death, a string of mysterious code pulls him into “Kiana’s Multiverse Harem Chat Group,” connecting him to worlds including Honkai, Genshin Impact, Honkai: Star Rail, and UT.

In the cracks between multiverses, he clings to life. His body gradually falls apart after he consumes a “Black Apple,” yet he remains determined to stop Errorization from spreading. To gain power, he disguises himself, deceives others, and even rewrites entire worlds. When he reunites with his younger sister Ling Xi from a parallel world, both of them are battered remnants of “Error” and “Void.” Caught between love and sin, and guided by a chat group spanning dimensions, Ling Yu will join Kiana, Elysia, Ying, Xing, and companions from other worlds to face the Honkai disaster, the encroachment of Errorization, and the shackles of their own fates.

The story is based on the concept of “Replacement Universes”: worlds with the same origins diverge into very different stories when key points in time change. The protagonists’ world follows a completely different path due to a change at its starting point, although its environment remains largely the same. In the multiverse, “Errorization” is a virus that transcends the laws of reality. It can infect all data and matter, turning the world into distorted gibberish. The chat group is a bond that spans dimensions, connecting the fates of different worlds and serving as a driving force behind the story.