The Skeen were demonic beings found in the mythology of Aantooine. They initially appeared as mere green humanoids similar to the Yevetha. When engaged however, Skeen would unleash a set of pointed wings from their backs. They then became an aerial force that could easily fly over positions and emplacements to capture fortresses and the like.
It was said that B'k'shr led an army of ten million men against the Skeen. In what was known as the Serpent's War, humans and Skeen fought viciously against each other for control of the Crom Territory. Ultimately, B'k'shr defeated the forces of the Skeen and became king of the territory for many decades.
This semi-historical record is disputed by some, classifying the story of B'k'shr versus the Skeen as mythology, however in 204 BBY, the remains of a winged humanoid were discovered in a cave near Crom on Aantooine that could likely have been one of these beings.
It was unclear if the Skeen were related to the Stenax.