After finding out he is the son of the great leader of Ohu, Gin, Weed sets out on a journey to find his father. However, with many friends to find, there are many enemies.
Denji has a simple dream—to live a happy and peaceful life, spending time with a girl he likes. This is a far cry from reality, however, as Denji is forced by the yakuza into killing devils in order to pay off his crushing debts. Using his pet devil Pochita as a weapon, he is ready to do anything for a bit of cash.
Hajime Hinobori is a grade 7 student who loves Battle Spirits. His parents leave him to research Battlefield Systems for the International Battle Spirits Association. Hajime is left under the care of their dear friend Dr. Denjiro. Then, Hajime finds a completed a Battlefield System demo machine. He will now fight as a Test Battler and is incredibly excited by the Spirits materialized in the Battlefield!
In the year 2024, the world has collapsed. Grotesque monsters lurk amongst the ruins of Japan, while remaining people scrape together what they can to survive. Kiruko, an odd-job girl in Nakano, accepts a mysterious woman's dying wish to take a boy named Maru to a place called Heaven. Maru is convinced that there will be a boy there who looks exactly like him.