Xerneas (Japanese: ゼルネアス,Zeruneasu) is a new Pokémon that is a Legendary Pokémon to be released in Pokémon X and Y. It is unclear what type of Pokémon it is and may be based on a Chital. In the glint of its eyes is the shape of the letter "X", hence the title of the game and when it stands, its body seems to be in the shape of an "X".
Its name may be reference to the Celtic "Horned god", Cernunnos. Its form may be a reference to Norse mythology guardians of the Yggdrasil Tree: a bird-like creature that protects the top of the tree, this may be Yveltal, a deer-like creature that protects the soil and trunk of the tree, this may be Xerneas, and a snake-like creature that protects the underworld below the tree. If this is right then there might be a snake-like legendary Pokémon to go with Xerneas and Yveltal.
Its name may start with an X because it represents the X axis in the 3D axis of X,Y and Z.
Xerneas is the second Pokémon to have a name to start with X, the first one being Xatu.
Xerneas is the only legendary Pokémon which name starts with X.
Xerneas is the first legendary Pokémon to have more than 2 horns.
Xerneas bears a resemblance to the Legendary PokemonArceus due that it legs are a similar form and Sawsbuck due to it looks like a Deer, has similar horn except Xerneas has multiple horns that are small, that are multicolored, and that branch off like a tree.
Xerneas resembles the Deer Spirit "Shishigami" from Hayao Miyazaki's film, Princess Mononoke.
In Xerneas's pupils of x's refering to him being the mascot of Pokemon X version