Future Card Buddyfight Episode 40: The Darkness of Dragon World!
Episode 40 of 64 of Future Card Buddyfight, aired October 11, 2014, 25 minutes. Available with English subtitles and dub where released.
Episode summary
"Disaster strikes twice for Gao and the gang! Shido and Davide wield the sinister powers of their new decks, built with cards from the mysterious Darkness Dragon World! Until now, this world was just a myth, but now its monsters are coming alive!" Source: crunchyroll