In Xerneas's animation,

Hundreds of years before the events of Poké mon: The Cocoon of Destruction and Diancie, Yveltal almost destroyed all living things in the Oro People's Forest. Saved a lot of Poké mon, including Little Diamond Dai, and repaired the damage.

If the sacred diamond in the diamond-mining country disappears, the whole kingdom will disappear with it. Princess Diancie couldn't make an eternal diamond, so she began to look for Xerneas. After Diancie found Xerneas, the latter said that he knew about Diancie's predicament, and told Diancie that this ability existed in Diancie himself, and then he imposed a demonic atmosphere on Diancie.

Later, after Yveltal was awakened again and caused serious damage, the Rockets, Marilyn Friem, Ninja Laerte, Miris Thief and others cooperated with Xerneas to protect Xiao Zhi and his party from Yveltal's Death Wing. Xerneas immediately used the goblin atmosphere to calm Yveltal's anger, and used the earth control to revive the people petrified by Yveltal. When using geodetic control, Xerneas becomes a tree. When asked if this meant death, Xerneas replied that this was just the beginning of a new life.