The Final Battle is a secret episode in Shin Megami Tensei Trading Card: Card Summoner. This episode resembles a traditional Megami Tensei game with 3 endings. This episode can only be played if the player has acquired at least 80% of the cards in the game, beaten "Path to Victory!" over level 60 and "Friend or Foe?" over Level 99 and under the Neutral alignment.
After defeating his sister and the "Devil Busters", Yuuji Kino and Yuri Takano can finally live in peace. 3 years after the championship, the spirit of Master Karl, who died in battle, returns and explains that everything that happened is Yuuji's fault, because he had defeated Karl. Karl's title of champion was a curse he was holding to protect the world from Lucifer, he who created the game to bring Chaos to the Earth by humanity's own hands. Only someone foolish enough to fight demons all his life and to keep his title of Champion would be the perfect defender of Earth. Because Karl was defeated, that task passed to Yuuji as the new champion. The demons would destroy everyone in the champion's life to make them not hold back and continue fighting. After that, all the demons would reach Earth if the new champion opts to live with someone else after the demon's attack, and shows to Yuuji the current situation of humanity: Yuuji and Yuri, who are the last humans on Earth. In order to change it, God Yahveh sent to Earth the Herald Metatron and his angels to defeat the Tyrant Lucifer and his hordes. Now Yuuji must accept his fate to become the savior of humanity, keep his life as it is, or join the demons to rule the world.