Once a chief River God, Achelous is the son of the Titans Oceanus and Tethys. Achelous traveled to Claydon to search for the daughter of King Oeneus and Queen Althea, a mortal named Deianira. Deianira was also an interest of Hercules and so, Achelous challanged him for Deianira's hand in marriage. As the battle raged on, Achelous transformed into a bull and charged at Hercules. He avoided the attack and shattered Achelous' right horn. With a hatred towards Hercules, Achelous agreed to help Eurystheus, Hercules' cousin and bitter rival.