Intrusion into the Mortal World

Xu Xiangyang had two good friends, one was the neighbor girl who lived in the same alley, and the other was the girl class president from the class next door;
Xu Xiangyang had a secret he couldn't tell anyone, he knew that one of his two friends was harboring a Demon King that could destroy the world......
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This is a story that took place at the end of the last century, where boys and girls depended on each other, warmed each other, and walked together towards happiness; a youth story filled with thrilling moments, nostalgia, and warmth.