In Greek mythology, Orthrus (also called Orthros, Orthos, Orthus, Orth and Orphus) was a two-headed dog and a doublet of Cerberus, both whelped by the chthonic monster Echidna by Typhon.
He was owned by the three-bodied Titan, Geryon. Orthrus and his master, Eurytion, were charged with guarding Geryon's herd of red cattle in the "sunset" land of Erytheia ("red one"), one of the islands of the Hesperides in the far west of the Mediterranean. Heracles eventually slew Orthrus, Eurytion, and Geryon, before...... [wikipedia.com]