Thor’s brother Balder the Brave almost made the cut for Thor: The Dark World, but was apparently removed from the film before its script was finalized.
Reported by CBR, concept artist Charlie Wen posted newly revealed art on Instagram with the caption “What Thor’s other brother almost looked like. Revisiting my #balder design post from earlier before I leave #thorthedarkworldbehind.” One half of the art depicts Balder wearing armor, a fur cape and wielding two swords while the other half shows Thor taking down enemies in a snowy field.
Source: IGN.com Thor's Other Brother Was Almost in Thor: The Dark World