Mystery: Starting from the Shadow World

An unknown silver medal, a predetermined fate.
The dead boy is reborn with the infusion of a new soul and embarks once again on the extraordinary path known as the Prisoner.
Desire and hope, shadows and embers, reflections of all beings, and from the abyss of the soul, a suffocating roar echoes...
......
Faced with Arrodes' question, Klein leaned back in his chair, lowered his eyes slightly, and murmured, "He's a very... hard person to judge. During this short trip, Philip helped me a lot, even though there were times when he did things that made me both laugh and cry."
"Even if we sometimes have different stances, it's undeniable..."
"He is my best friend."
......
Lord of Mysteries fanfiction, The Prisoner's Path
PS: The protagonist carries the "Shadow World" source matter, is unaware of the original plot, and travels to a time roughly the same as Zhou Mingrui's.