From Smith's Dictionary of Greek and Roman Biography and Mythology

EMATHION

a son of Tithonus and Eos, and a brother of Memnon. ( Theogony of Hesiod) He was king of Arabia, and was slain by Heracles. (Apollodorus ii) There are two other mythical personages of this name. (Metamorphoses by Ovid v. Aeneid by Virgil ix)