Future Card Buddyfight

Humans intermingle with beings from the parallel world of "Shinkinkai." The "Buddyfight" game chooses humans ("Buddyfighters") and partners them with Buddy Monsters from Shinkinkai, and the duo fight against other Buddyfighters. The battles in these games can sometimes even influence the fate of nations. Gaō Mikado is a sixth-year student at the "Aibo Academy" elementary division who longs to be a Buddyfighter and to be partnered with a Monster. One day Gaō notices a young boy being bullied by delinquents, and he helps him out using his Aiki-jujutsu skills. Drum Bunker Dragon, a Monster and the son of the hero of Dragon World, watches Gaō's actions, and decides to form a pact with him as his buddy.

(Source: Anime News Network)