Reshiram is a white, bipedal Pokémon with characteristics of dragons, birds, and mammals. Its elongated, voluminous mane flows from the upper side of its snout and extends outward from its head. The top of this mane features two protrusions resembling ears. Reshiram's face is lined with spiky features, and it has a small, pointed extension beneath its chin. Its eyes have blue irises and black pupils. When its mouth is open, two pairs of pointed teeth are visible—one pair in the upper jaw and one in the lower.
Reshiram possesses a long and slender neck, adorned with a fluffy, collar-like protrusion emerging from two gray, glass-like neckbands. Its arms start off slender but then widen into a more wing-like appearance, featuring four claw-like appendages on the leading edge that resemble hands. There are plates at the back of Reshiram’s "hands," which share a similar color to its neck rings. On its chest, Reshiram has a feathered or furry feature, with the lower part jutting outwards to a point. Long, feather-like protrusions extend from its thighs. Its feet have large gray claws—three at the front and one at the back, giving an impression akin to high heels. Reshiram's tail is a complex array of plume and ribbon-like extensions, encircled by two large bands similar to those around its neck. When its emotions intensify, it enters Overdrive mode, causing its tail to emit a fiery glow.
Reshiram has a jet engine-like tail that helps it accelerate during high-speed flights. It can release flames from its tail to incinerate everything around it. By flaring its tail, Reshiram can influence the atmosphere and alter the weather. This Pokémon enjoys treats made by Snacksworth, who once encountered it.
In Unova mythology, Reshiram allied with the older brother who sought truth. As such, it holds a strong belief in truth. Reshiram is considered Zekrom’s equal in battle, meaning neither dragon can truly defeat the other. Both possess the power to destroy their region if necessary. If Reshiram's body is destroyed or if Kyurem’s tendrils touch it, Reshiram can transform into the Light Stone. It can revert from the stone when awakened by a hero who believes in truth. According to legend, Reshiram is said to burn down kingdoms of people consumed by greed and ignoring the truth.
