Warriors Orochi 3: Ultimate - The Demise of Orochi X (Chaos)

This is a real final battle, unlike Into the Fire. Koshi Castle has been upgraded from WO1/2 and is freaking huge now. Orochi's forces are all over the place and you have to break sacred orbs scattered across the map before you can reach Orochi, who is defended by Kiyomori, Gyuki, and Dodomeki. Susano'o also shows up as reinforcements as a third force. Fighting Orochi himself is a bit disappointing though, as he doesn't put up much a fight due to this game having some awful balancing. Which is a damn shame cuz the intro and the song is pretty awesome.

The Good Ending leads to everyone being happy that Orochi was defeated and goes back to living their normal lives in his world. The Ultimate story line continues from this ending.