I Reincarnated as an OP Character Who Was Completely Irrelevant to The Story

Neon Light, a modern-day Japanese RPG, is a game I dedicated my life to, playing through it multiple times, Now, I stand—no, I've been reincarnated—in the very world of my dreams. My reincarnated character is Lux, a tired-looking salaryman type I've never even seen mentioned in the game's dialogue. He's an overpowered character so strong it makes me worry about breaking the game's balance. Despite trying to live quietly so as not to disrupt the game's storyline, I've ended up saving characters destined to die and earning the respect of the final boss even more than the main protagonist—how did this happen!? An unknowingly overpowered character in an off-script adventure! A new kind of otherworld fantasy!