After Manabu and Uratane each get the Xerneas and Yveltal half decks, respectively, they rebuild them to better suit their play styles and immediately start to battle. It is then that Manabu learns that attacks need certain types of Energy in order to be used, due him attaching only Fairy-type Energy and failing to use his Talonflame's Flare Blitz attack. Manabu loses the battle as a result of that blunder, and Uratane then explains to him that that type and number of Energy cards, as well as resistances in a deck, are very important when building one. Taking what Uratane said to heart, Manabu rebuilds his Xerneas deck with those aspects in mind to focus more on Fairy-types, and challenges Uratane to another battle. Manabu easily wins thanks to the resistance to Dark-types that Fairy-type Pokémon have.
This article is part of both Project Manga and Project TCG, Bulbapedia projects that, together, aim to write comprehensive articles on the Pokémon Manga and TCG, respectively.
