Once satisfied with all desired things completed, approach the rainbow bridge at the altar at the edge of Laochi Lake. Cross the bridge, and observe the cutscene that ensues. After the conversation of resolve, Amaterasu will be within the antechamber of the Ark of Yamato. Move forward, and one of the remaining spirits of the Celestials, Marco will greet her. Right now, the interior of the Ark is a threatening red, instead of Moon Tribe-pulsing neon blue and there are five paths that branch from the central platform. Each path will lead to a certain boss battle against all the major bosses that were previously defeated, Lechku & Nechku not included (Spider Queen, Crimson Helm, Orochi, Blight and Ninetails). On the path to the first, third and fifth boss, three other spirits of the Celestials, Hakuba, Sado and Azumi, will be encountered. They only provide background informations of the Ark of Yamato and the genocide that ensued, though.
After all the bosses have been defeated, the Ark will be turned back to its original Moon Tribe-pulsing neon blue color. Meet Marco for some last-minute shopping to be prepared for the massive boss battle that is going to take place. Then, step in the central platform's now unlocked teleporter. Marco will bid Amaterasu farewell before she engages in the boss battle that will define the fate of Nippon.