Lu Mingfei: What? They're all real!

This book is also known as "Where Did My Red-Haired Wife Go?", "Chen Motong: Oh No! I've Become a Substitute!", and "Lu Mingfei Gradually Understands Everything".
[Multiple female leads] [No rebirth, no premonition]
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One day, Lu Mingfei bumped his head and gained some new memories.
He recalled that he seemed to have sat on a divine throne, as if he were the supreme being, with a red-haired wife who could not speak beside him.
He also recalled that he seemed to have been locked up in a mental hospital, where he lived with a girl named Renata and they escaped together.
There was another red-haired girl who looked like the wife, but her tragic fate was pitiful.
And that's not all; he remembered so many other things...
Lu Mingfei was overwhelmed with emotion by his magnificent memories, but little did he know that he would slowly discover that... those bizarre memories were all real, and that they were all actually real!
……
Chen Motong huddled in the corner, hugging her knees. She couldn't understand, and couldn't believe. She didn't understand how she, who had met him first, could end up as a "latecomer's" shadow.