PROLOGUE

"A project failed. A life began."

He thought his sister was lost forever. Until she came back... as something else.

Five years after his sister vanished without a trace, psychology student Murakami Nijiro discovers the truth: she's alive - but now known as Subject 27A, a broken soul fused with something inhuman by the secretive Demon Suppression Bureau.

With the help of his best friend Junpei, and a half-demon named Mei, Nijiro enters a world shaped by memory, emotion, and corrupted science. At its center lies Project AETHER-X, an abandoned experiment that never truly ended.

As the Bureau closes in and Rui's identity begins to fragment, Nijiro must decide what's worth saving: the sister he once knew - or the person she's becoming.