>The Useless Katana, Cursed by the Sword Spirit
MC (in Sengoku period Japan) stumbles upon a massacre, where an entire royal caravan has been slain except for one guy, who harakiri'd himself. Harakiri man tells MC that his katana cannot kill its target, and that he seppuku'd to ensure he lived long enough to pass it on to its next owner, then begs MC to kill him with his regular katana. MC regrettably obliges. MC obtains the useless sword. Miraculously, with each surely-fatal finishing strike, it leaves survivable wounds and ensures the target lives. MC, after grappling with how fucking stupid and useless this is in multiple bandit encounters, meets the daughter of the Daimyo in a wealthy town as a worthless broke ronin. He learns that the daimyo is close to death and his sons are waging bloody war to obtain the throne once he passes.

MC orchestrates a false flag fake assassination of the daimyo while collaborating with best girl (daughter) to ensure her chosen brother reaches the throne. After the main competitor to the throne learns of this, he sends his assassin to kill MC, who happens to wield the Katana of Instant Death which, unbeknownst to him, kills the target closest in spirit to the victim instantly. This assassin is in love with Daimyo's daughter. MC "kills" him in the sword duel, takes his Katana of Instant Death and then uses it to defeat the other competitors to the throne, leaving behind a wake of destruction. Finally, the new Daimyo is chosen, and MC is given the title of protector of the Princess and learns of a sword-maker who can synthesize magic katanas.

He brings the two katanas to the sword maker. He combines them and produces a katana that only brings misfortune to the user once his objectives have been achieved. After his house burns down, his mistress dies, and the Princess is struck by a mysterious illness, he seppuku's out of grief with the sword while on a caravan to deliver gold to a nearby principality, repeating the story again.