1 week later, the 3rd Shōgun states that their most Sacred possesion has been lost named the Bushido Treasure, Bō (the Bushido Treasure is said to be seven weapons made by the gods themselves.) After some serious investigating, they find out that it is Seijūro so Nashikaze sends a group of aonisaibushi including Tagosaku to retrieve the Bushido Treasure. Meanwhile, Nashikaze leaves a Heimura for a bit and meets a tomb. The tomb had been covered in purple with a mysterious aura. Out came, a Shinobi named Shinosuna. Shinosuna introduces himself and states that he wants darkness to reign not just in Japan but also the whole world. Nashikaze and Shinosuna have an intense fight.
Near the end of the fight, Nashikaze attempts the Sealing Current Tomb which seals someone into a nearby tomb. Unfortunately, it fails and Shinosuna almost kills Nashikaze but decides to spare him as he senses Seijūro's seizan. Meanwhile, Keiko and Keiji ends up in a desert finding Chujitsuna, Hiretsuna's comrade. As Keiji is being held down, Keiko unlocks her Hadāmaku Style named the Ikari Mark and kills Chujitsuna with Keiji being impressed with this. The rest find Shinosuna. Tagosaku and the rest try to fight him but they end up taking a fat lost. Even though Keiji and Keiko with her new powers arrives, isn't enough to handle Shinosuna. Finally, Haruyo arrives and attempts to use her seizan releases on him which only effects him a little.
Seijūro, later reveals that he will betray Shinosuna and joins Kensei's side much to Kensei's happiness. Shinosuna obviously being annoyed about this releases his full power and attempts to kill Seijūro but Haruyo steps in and sacrifices herself. (RIP). Kensei being enraged full extracts Raijin's seizan and becomes much stronger than before. The final battle arrives with Kensei, Seijūro and Tagosaku fighting Shinosuna. Of course Kensei tries one of his POWERFUL speeches, but it seems, it wasn't effective. Kensei and Shinosuna have their fight because remember kids, violence solves all problems. At the climax of their battle, Kensei preforms a special technique named the Crossfire Slashes and successfully kills Shinosuna, avenging his mother.
Unfortunately, Kensei and the others arrive at Heimura to see a big tornado engulfing it causing the death of Yoshi Heiwa and Nashikaze Heiwa. Seijūro finally states that he was never on their side and he was the one who caused the tornado and also states in 3 years, he will gain new power and strike again. So, Kensei and the others decide to train as hard as they can for the next 3 years.
And with that brings us the ending of Season 1 of Bushido.