Even a Good-for-Nothing Swordsman Wants to Be a Savior

Nagano Hiro transmigrates to the late Tokugawa era. His parents support ending Japan’s isolationist policy and are forced by the shogunate to commit seppuku. After joining Tennen Rishin-ryū, Nagano Hiro takes the name Uchiha Hiro. He meets the genius swordswoman Okita Souji and obtains the Yu-Gi-Oh! System. Step by step, he grows stronger, exchanging for items from various games until he becomes the savior of his era!

(This isn’t entirely a Type-Moon fanfic. Only Type-Moon characters appear early on, but characters from other IPs will show up later, so you could call it a crossover mash-up.)