Yveltal is a large avian-like Pokémon. Its body is dark in coloration and is adorned with grayish patterns along the underside. Yveltal's wings and tails have three points extending along the edges, close to where they meet the body. There are five large claws on each appendage, three of which curve inwards. Yveltal's underside is bright red, with branching, black markings. Similar markings are present on Yveltal's head and neck.
Yveltal has a pointed, beak-like snout. Black horns extend from above its blue eyes, with a sharply curved portion pointing forward and thinner prongs facing the rear. A feathery gray ruff encircles its neck and billows out over its back. Yveltal has small, birdlike legs with powerful talons. Like the rest of the underside, the legs are red with black adornments, and the talons are gray. Each foot has two toes facing forward and one pointing backwards. When Yveltal's wings and tail are fully extended, Yveltal resembles the English letter Y.
Yveltal has the power to absorb life energy. When it reaches the end of its lifespan, it expands its wings and steals all of the life energy of every living thing around it before transforming into a cocoon to sleep for 1,000 years. Yveltal is the only known Pokémon capable of learning the move Oblivion Wing.
- Yveltal Will soon appear in Team Robot in Pokemon: Diancie & The Cocoon of Destruction, Hundreds of years prior to the movie's events, Yveltal almost destroyed all life in Allearth Forest. Xerneas saved Dace and many other Pokémon from the destruction, and later reversed all the damage Yveltal did. After this, Yveltal turned into a giant cocoon and slumbered until the events of the movie.
Argus and Millis Steel, Marilyn Flame, and Ninja Riot also, all of the villains were fighting over who should catch Diancie. They eventually took their fighting to an underground pool in which Yveltal slept, in its cocoon form. The fighting eventually awakened Yveltal, and it immediately activated its Dark Aura, then used Oblivion Wing to petrify large areas of the forest, as well as Team Rocket, Major Nixel, Verminious Snaptrap, The Villains, Team Robot's Allies, 3 DigiDestined And Their Digimon, Marilyn, Riot, the Carbink servants (save for Dace), Bird Brain, Zach Varmitech, Donita Donata, Gaston Gourmand, Etemon, Bat, Owl, Zippy, Zackbots, Mal, the Cockroaches, Mutated Animals, and the Steels, who tried to stop it with missiles from their ship. Ash, Pikachu, & Mane 6 tried to battle Yveltal as well, but almost fell off a cliff (with Pikachu, Mane 6, Jorge, Eddie, & Dulcy being petrified in the process). Diancie then Mega Evolved and created a large diamond, which she used to protect Ash, Serena, Clemont, Bonnie and everyone from another Oblivion Wing. Yveltal then used Oblivion Wing once again to finish them off, but the attack was intercepted by Xerneas' Aurora Beam. Yveltal, still in its Dark Aura state, used Shadow Ball, which Xerneas intercepted with another Aurora Beam before using its Fairy Aura to successfully calm Yveltal. With nothing more to do, it flew away peacefully.
Yveltal was last seen flying through a mountainous area at night during the credits.