Yveltal possesses avian and draconian traits. It has large wings and a tail that are red colored internally and black colored externally. It has intense teal-colored eyes with white pupils. When Yveltal straightens its arms in flight, it forms the shape of a Y. Its talons are also Y-shaped. Yveltal is part flying type, and based on the concept of the y-axis.
Yveltal represents destruction, such as natural disasters, while its counterpart, Xerneas, represents new life.
When Yveltal is about to reach the end of its lifespan, it steals the life force of everything living around it, then transforms into a cocoon to sleep.
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 is Zygarde. It is part of Yggdrasil Trio.
Yveltal starts with the letter Y because it represents the Y axis (or the vertical one, and as Yveltal is in the sky, it’s a perfect fit!) in the 3D axis of X, Y and Z.