Othros was the youngest sibling in the family. And since he wasn't as scary or as strong as the rest his parents gave him to Geryon the three bodied Giant.
Orthros spent most of his days doing what herd dogs did. As he grew he became fast and skilled in herding and other things. So when Hercules came to steal the herd he wasn't going to let that happen. He fought Hercules using his great speed to run in circles around Hercules, which created a huge tornado.
Hercules was swept away by the tornado but unfortunately so was the house and half the herd. But Geryon wasn't that mad and celebrated with Orthros. By the end of the year Geryon had twice as many cows and an even bigger and better house with a swimming pool.