Tsurumaru Kuninaga once sighed to Ichigo Hitofuri, who was fussing over his younger brothers: "Good thing I don't have any siblings."
He didn't want an older brother ordering him around every day!
Then the Time Government introduced a sword who claimed to be his older brother.
Tsurumaru: "?"
Where did this brother come from? How had he never heard of him?
*
The summoned Tsurumaru: "Heiraku Kuninaga, answering Aruji's call. You may call me Tsurumaru. I have no memories to match, but I hear that the Tsurumaru Kuninaga of later generations is me."
Tsurumaru, whose name had even been stolen: "...?"
*
A transmigrator who traveled to the Heian era sought out the swordsmith Goto Kuninaga. They described the shape and features of the famous sword Tsurumaru, hoping to become the first person in history to own a sword called Tsurumaru Kuninaga.
In the transmigrator's hands, Big Brother Tsurumaru cut a swath through his enemies, with miraculous abilities such as "paralysis," "sleep," "revival," and "area attack."
The real Tsurumaru: Wait, are those really abilities a tachi should have?
To avoid confusion, the Time Government officially renamed Big Brother Tsurumaru "Heiraku Kuninaga."
Heiraku Kuninaga looked exactly like Tsurumaru Kuninaga, and their blade engravings and shapes were identical. Their personalities, however, couldn't have been more different.
The one who called himself Tsurumaru's older brother was mature, steady, old-fashioned, (socially anxious), (a bit of a dummy)...
His memories were muddled. He couldn't remember his own deeds, but he could more or less recount what had happened to the real Tsurumaru and claim it as his own. He insisted he was the very Tsurumaru Kuninaga whose legacy had been passed down through history for a thousand years.
When the others in the citadel questioned him, he talked his way through it: although he and Tsurumaru were different swords, their early lives differed because they had different previous masters, making them from parallel worlds. But later, they had the same experiences and legends, and their blade engravings and shapes matched, so there was nothing wrong with him also being called Tsurumaru Kuninaga!
And since he had been born in his parallel world earlier than the Tsurumaru Kuninaga recorded in this world, there was nothing wrong with calling Tsurumaru his younger brother and taking care of him!
To sum up, the real Tsurumaru (the younger brother) was his parallel-world self!
Everyone in the citadel: I almost believed him!
*
Big Brother Tsurumaru, who thought he could cut a swath through his enemies, returned gravely wounded from a sortie to Hakodate. A mutated tsukumogami who couldn't gain experience to level up was guided by the Time Government and set out on his training journey at level one.
But his former master had transmigrated through too many worlds, so he had to train again and again, traveling to places like the Hunter world and the Prince of Tennis world to find his lost memories and unlock his sealed skills...
Big Brother Tsurumaru: Aruji, what should I do? I'm almost out of training tools!
Theme: Even if you share the same experiences and life, that doesn't mean you're the same person
