He is (allegedly) the personal tantou of Minamoto no Yoshitsune. Dressed like a tengu as an homage to his owner having allegedly been trained by one. As he said in his introductory line, he was there from his owner's time at the temple to his very last moment.
Ima-no-tsurugi is a straightforward and cheerful child, treating fighting as though it's a game and boasting himself of being the fastest tantou. He has an extraordinary sense of balance and can jump about cheerfully on one-toothed geta. Despite his bonds with Minamoto no Yoshitsune, Ima-no-tsurugi is very loyal to the Saniwa, who he puts before himself. He's often seen hanging out with Iwatooshi, due to their masters' shared past.
After his Kiwame remodel, it's revealed he's a fictional sword and never interacted with Yoshitsune at all. Despite this, he understands that he exists because of the Saniwa, and vows to stay by their side and help them.
