GhostParser
Alan Han is a college student who, after failing to log into Resident Evil 9 and getting so frustrated by an error code that he literally dies at the age of 21, unexpectedly finds himself transported into the world of Resident Evil.
Right from the start, he's greeted by a young man in casual clothes pointing a gun straight at him.
After surviving countless dangers, he eventually escapes Raccoon City alongside Leon.
In the end, he returns to Raccoon City with Leon once more, stepping onto that land again to face the final biohazard together.
"I only acknowledge the one who crawled out of hell with me."
(The story begins from the timeline of Resident Evil 2. No romance. Focus on the main plot with some slice-of-life elements. The protagonist is not overpowered, he starts as an ordinary college student and grows gradually. Side stories may be included later.)