Transmigrating into Attack on Titan as Armin

A young man from Blue Star, furious after watching the final season of Attack on Titan, suffers a cerebral hemorrhage and transmigrates into the world of Attack on Titan. Taking over the body of Armin, a Titan shifter, he vows to do everything in his power to give Paradis Island a perfect ending!

The story begins in the third year after they saw the ocean. Aside from knowing the original plot, the protagonist has no other golden finger and relies entirely on the characters' own abilities.