This video shows the final battles of the game, the ending, and the credits. I begin the game from the final save point which is located in the underground ruins right before your final encounter with the red testament. During the final battles I have access to the Erde Kaider Sigma, which makes the final battle way too easy. Given this, and the fact he can kill the final boss with two summons, I decided to be a little more sportive and defeat them without using any Erde Kaiser summons.
The first battles are with the red testament as he tries to force Shion to join him and Wilhelm. The first battle is a joke but the second battle gets pretty crazy when he starts to use his overdrive master spells. After this is the final battle with Zarathustra which can kill your entire party if you do not put an auto life spell on your characters such as, safety level or best ally.