The CONCEPT of Satan - using that name - and referring to a particular, evil, supernatural being - first appears in the Old Testament. The oldest mention is probably that found in "The Book of Zechariah", which critical experts date to about 520 B.C.E. *** Hades - the Greek deity and ruler of the dead - dates to at least the early 7th c. B.C.E. - i.e. at least 150 years before Zechariah. *** Note that the two are not very comparable. Satan is the supernatural enemy of the Jewish God, Satan being typically described as an evil being working contrary to the design of the Jewish God, not a deity in his own right (i.e. not identified as such AND not worshiped as such) and not ruler of the dead or deity of the dead. On the other hand, Hades is one of the three most powerful and important Greek deities, brother of the ruler Zeus, and a deity that rules the dead. In literature he is typically NOT described as evil (not from the perspective of "the gods") and NOT described as working counter to the will of his brother Zeus. *** I always find it sort of odd that most modern fiction depicts Hades as evil and (typically) a betrayer of the Greco-Roman deities, when that sort of characterization is typically not found in Greco-Roman myth. Indeed: in Greco-Roman myth "the Olympians" tended to be much more mercurial - and prone to maliciously harm humans - than Hades.

Hades in Greek means the grave or the land of the dead. Satan came first, he had already existed as an angel of God before the Earth was created. Isaiah 14:12 "How art thou fallen from Heaven, O Lucifer, son of the morning! How art thou cut down to the ground, who didst weaken the nations!"