You know what it's like having an older sibling who takes all the glory? Well that's exactly how Orthrus felt. His brother was Cerberus, the famed three-headed dog who guards the entrance to Hades. You can imagine what it was like for Orthrus - not only did he only have two heads, but he was slain by Hercules when guarding the cattle of Geryon. Still, at least he had a snake's tail, which is more than can be said for Cerberus.