Pokémon X and Y Legendaries Xerneas and Yveltal have been fully detailed, with new information released on their types and moves.
Xerneas is a Fairy type Pokémon and can perform the exclusive Geomancy move, while Yveltal, a Dark and Flying-type Pokémon, is able to make use of the Oblivion Wing move.
Xerneas: A new Fairy type being introduced in Pokémon X and Pokémon Y. Xerneas' exclusive move is Geomancy, which features rainbow-coloured light that erupts from the earth around it. Xerneas has the special Ability Fairy Aura, which naturally takes effect in battle, strengthening Fairy-type moves for all Pokémon in battle. Be careful, because Fairy Aura also has a positive effect on opposing Pokémon that know Fairy-type moves.
Yveltal: A Dark and Flying type is the only Pokémon that can learn the move Oblivion Wing, which sends Yveltal flying high into the sky to release a powerful beam of red light that scorches the ground below. The Destruction Pokémon's special Ability, Dark Aura, is a counterpoint to Fairy Aura, raising the strength of Dark-type moves for all Pokémon in battle. This Ability is powerfully effective in Double and Triple Battles when facing multiple opponents simultaneously. So, when Yveltal is in battle, it's smart for players to fill their team with Pokémon that can use Dark-type moves.
Pokémon X and Pokémon Y release on October 12 for Nintendo 3DS.
Source: Pokemon Company Press Release