Marvel: Kamen Rider OOO, The Final Chapter of the Coins

Sima Yin transmigrates by accident, landing in Tokyo, Japan, where he encounters Ankh, who has lost an arm. Mistaking this for the world of Kamen Rider OOO, he carries his three starting Core Medals (Eagle, Tiger, and Grasshopper) and stows away to America to escape Ankh and the Greed. There, he runs into Tony Stark, who has just been rescued from Afghanistan, and realizes he is in the Marvel Universe. His entire understanding of the world falls apart.

(Some details differ from the original timeline. The story is written from the author's personal perspective, and events may happen earlier or later than expected. Please understand.)