The Branded are those who are born of both a Laguz and Beorc parent. The Branded's children will also be Branded. Those who are Branded are considered parentless to Laguz. The union of both a Beorc and Laguz is said to be a crime against the goddess. The punishment of this union is dealt to the Laguz parent, resulting in a loss of their Laguz powers.
Various characters in Fire Emblem: Path of Radiance and Fire Emblem: Radiant Dawn are Branded, including Micaiah, Soren, Amy, Zelgius, Stefan, and many of the Apostles of Begnion (the descendants of the Heron, Lehran, and the Beorc woman, Altina).
The Branded try to hide their brand so that they are not judged by Beorc and Laguz. Hiding the brand from Laguz however is much harder because many Laguz feel uneasy around them. Hiding the brand becomes harder as years pass, as the Branded age differently from Beorc depending on what Laguz they are Branded from. For example, Branded Dragons will age much slower than the Branded of any other Laguz.
When Stefan meets the goddess Yune, he explains that the Branded are cursed and tells her of how it is said to be a crime against the goddess. Yune, however, knows nothing of this and wonders how history got twisted. In an attempt to get Ashera to free all the petrified people on Tellius, Yune tells Ashera that people can be born of a Laguz and Beorc parent, showing that even Ashera did not know of the way the Branded was treated.