This section temporarily contains information copied directly from Bulbapedia, and needs to be rewritten so not to be classified as plagiarism.
Yveltal is a large avian-like Pokémon. Its body is dark in coloration and is adorned with greyish 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 grey 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 grey. Each foot has two toes facing forward and one pointing backwards. When Yveltal's wings and tail are fully extended, Yveltal resembles the Latin letter Y.