Xerneas made its debut in Diancie and the Cocoon of Destruction, alongside Yveltal. It granted Diancie its Fairy Aura what Diancie is looking for. Later, it calmed down the awakened Yveltal and returned anything Yveltal petrified into normal. As a result, Xerneas changed into its tree form.
A Xerneas appeared as a silhouette in Foggy Pokémon Orienteering!. However, its antlers could clearly be seen.
- Xerneas is the only single-type Legendary Pokémon introduced in Generation VI.
- Xerneas has the highest Attack base stat and the highest base stat total of all non-Mega Evolved Fairy-type Pokémon.
- Xerneas has the same stat distribution as Yveltal.
- Xerneas is the only version mascot whose signature move is a status move.
- Xerneas is tied with Yveltal and Rayquaza for having the highest catch rate of all legendary Pokémon, with a catch rate of 45. This is likely due to Xerneas being a required capture during the storyline of Pokémon X and Y.
- Xerneas, along with Yveltal, was designed by art designers Ken Sugimori and Yusuke Ohmura. Initial design for the two Legendary Pokémon was started by Sugimori, but he encountered "artist's block", having a hard time coming up with concepts. For the first time, he gave the work over to another designer, Ohmura. Ohmura furthered the designs, after which Sugimori resumed to finish them.
- Xerneas is the tallest and heaviest Fairy-type Pokémon.
- Xerneas's Neutral Mode has no special animations that play in the Hoenn Pokédex, but it plays Active Mode's attack animations if tapped on in the Pokémon summary screen.