Tensei Shitara Slime Datta Ken (WN) - Chapter 330

Getting transmigrated inside a novel is not really a bad thing—you know the story, you have the power of the future in your hand, you know all the hidden keys. You might as well end up as the most powerful and omniscient being in that world.That is, if you don’t wake up during the epilogue.And yet I find myself in the body of a fallen priest at the end of the novel, a tragic hero who had his mana circuit broken in the last war, being shunned, drown in debt, and destined to die not long after.Fortunately, I know just the cure.Unfortunately, the cure was in the hand of one of the Demon Lords—you know, the race that my kingdom just wage war with.Would he give me the cure if I asked him politely? There’s no harm in trying, right? I’d die if I didn’t get the cure, anyway.“Sure, but you have to be my bride as the price,” the Demon Lord said....huh? Sir, you know I’m (technically) a priest, right?

In a world where strength determines one’s future, William, an orphan with no extraordinary talents, faces a grim destiny—until a brutal attack leaves him clinging to life. Instead of death, he awakens to a mysterious and powerful entity lurking within his mind: the Shadow System, a game-like interface that promises him unimaginable power. But this power comes with dark secrets, and refusing it would mean his death. Forced into a pact with a voice that can hear his every thought, William must navigate a dangerous new reality where shadow abilities and celestial power collide. As he enters the prestigious military academy, his newfound abilities draw both allies and enemies, all while a deadly conspiracy brews in the shadows. With the odds stacked against him, William must unravel the mystery of the Shadow System and decide whether to embrace the darkness within—or be consumed by it. His journey from a bullied outcast to a potential god will challenge not just his survival, but his very humanity. Power always comes at a cost—will William be able to pay the price? “What am I?” William asked the system. The system’s voice echoed in his head, cold and indifferent. “You are nothing.”

When I cleared the final chapter of a game that was a national failure, I became an unnamed side character in it.

A non-standard, unmeasurable, EX rank supporting character.