Sign-In System: One Piece, Demon Slayer & Beyond
Ron finds himself reborn in the world of One Piece, stranded on a remote island in the East Blue. But he's not just any ordinary child—he’s bonded to a mysterious sign-in system that grants him powers with every new location he visits.
At his first sign-in, he unlocks the legendary Sun Breathing Technique, along with a boost to his vitality. From Shitmotsuki Village to Skypiea, Enies Lobby to Marineford, Ron travels the world, collecting extraordinary rewards that make him a force to be reckoned with. The Raikiri, one of the 21 Great Grade Swords, Armament Haki, Observation Haki, and more fall into his hands.
As Ron steps onto the battlefield of Marineford during the legendary Summit War, the mightiest warriors—Four Emperors and Marine Admirals alike—pause, stunned by his presence. But Ron merely waves them off, "Don’t mind me. I’m just passing through."
Join Ron on his journey across the Grand Line as he signs in at iconic locations, growing stronger with every step. This is not just an adventure—it’s a legend in the making.
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This is a multiverse fanfiction starting in One Piece, transitioning into Demon Slayer, then to One Punch Man, and more.
If you’re only here for One Piece, feel free to stop when that arc concludes.
If you love crossovers, you can continue reading :)
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Access 40+ chapters in advance on my Patreon: pat reon.com /ElvenKing20.
ElvenKing20 · Anime & Comics
