When Su Bai cosplayed and fell into Tsurumaru, he traveled through time and performed the story of the script in various worlds.
First world
He is the unknown second Shintsurumaru Kuninaga in the Honmaru, who was imprisoned in a dark room and tortured. After solving the slag trial, he was unable to be accepted by the other swordsmen of Honmaru because he killed the trial judge.
Second world
The judge's love for Tsurumaru Kunaga made it difficult for him to accept Tsurumaru's contact with other swords, and placed a curse on Tsurumaru that would cause them to break if he came close to other swords.
Third world
The spiritual power of the examiner was not high enough to forge rare swords. Tsurumaru Kunaga was purchased by the examiner through the black market and became Honmaru's spiritual power center through the blade experiment.
Fourth world
The examiner is an Onmyoji. In order to improve the combat power of Touken Fusangshin, he conducted experiments to combine Touken Fusangshin and Shikigami.
…
Concept: Life is like a play, it all depends on acting skills