Dan wishes to have exciting battles like in Grand Rolo again. He gets his chance when Mai invites him to the future, where the humans are being conquered by demons. There, he joins the crew of The Beautiful Sophia, and creates a deck based upon the newest type of cards, Brave. (Source: Battle Spirits Wiki)
Watch Battle Spirits: Brave episode 1 online — subbed and dubbed, with automatic AniList / MyAnimeList progress sync.