El Diablo is a wild mustang that travels the wilds of northern Mexico.
El Diablo ran free through the wilds of northern Mexico in a herd of wild mustangs. He survived several attempts at capture by Mexican cowboys, earning him both his name and a reputation as being impossible to tame.
He was captured briefly by the joint Wilson-Bodie venture into Mexico and treated cruelly by cowboy Jed Begert. When Begert betrayed his employers for his true boss Chato, he tried to escape taking a woman hostage. El Diablo was tied close by and when able, trampled his abuser to death, broke his bonds and escaped.