After the conclusion of Offerings for the Shrine, Sanae interrupts your conversation to bring Acting Chief Takeru some bad news. Apparently the seal that was placed upon Sakurajima Depths has been broken, not by cutting or unlocking it, but through sheer brute force alone. Yoshitsune believes this to be proof that Momotarou may be around Kumaso Village.
Yoshitsune tells Acting Chief Takeru to set up defenses around the town until you can handle the situation. Since Tiamat the Kamikui is in there, you must head into Sakurajima Depths to clear the youkai and Tiamat out of the dungeon and find out who broke the seal.
You travel through the dungeon finding some passages were blocked due to the town folk placing ashes throughout the shrine to sanctify it more from the evils of the Youkai. You finally reach through the end of the shrine from tough battles with to find Momotarou and Tiamat. Lady Shizuka notices that Momotarou is wearing her hair pin and quietly asks for Momotarou to give the hair pin back charging straight into the pit containing Tiamat and Momotarou with you in tow.
In front of Tiamat, the battle becomes more difficult than the first fight you two encountered in Repairing the Seal. Tiamat does not hold anything back as he uses his multiple heads to shower you with fireballs and diving upon you with his air superiority. You were able to hold out and finally defeat Tiamat who you have been chasing since the start of your journey.
After the defeat of Tiamat, Lady Shizuka starts to head over to Momotarou to get her hair pin back when Yoshitsune stops her noticing that something is wrong with Momotarou and her suspicions become real when Crazed Momotarou begins to realize there is an Oni in the area. Asking the War Gods to bless him, he yells out his ultimatum to kill all Oni. You are now brought into a battle between Crazed Momotarou and yourself having to defeat him and his six-sword style. You charge without fear into this battle and swing and dodge through his barrage of attacks. Though his appearance originally brought fear into your eyes, your own skills seem to put his to shame as you seem to dance around and parry his own attacks where you finally deal the final blow to knock him out and return Lady Shizuka's hair pin that she lost in Onigashima. She is extremely grateful for your silent reply that seems to say she deserves this hair pin.
You return to Kumaso Village to bring the good news to Acting Chief Takeru who is extremely grateful for what you have done for their little town. Acting Chief Takeru is sorry to say that he doesn't have the grand award that an Oni of your caliber deserves for completing this quest for them due to the small nature of their town, but hopes what little they can give will be sufficient. Acting Chief Takeru wonders what you will do now that Tiamat is defeated and Yoshitsune says that they will be heading throughout the lands defeating Kamikui wherever a rumor of them shall appear. Before Yoshitsune can get another word in, Ibaraki Douji butts into the conversation to ask Miki the Sake Brewer for the famous sake of Kumaso Village that she originally came to this town for. With her alcohol appetite satisfied Yoshitsune thanks them again for their help and want to head off.