The Bible bears witness not only to God, but also to Satan. In the Genesis account of the Garden of Eden, Satan is described as a serpent, but in Revelation 12, he is described as a beast with seven heads and ten horns.

[ Revelation 12:3~9] And there appeared another wonder in heaven; and behold a great red dragon, having seven heads and ten horns, and seven crowns upon his heads....(9)And the great dragon was cast out, that old serpent, called the Devil, and Satan,

So what is this seven-headed, ten-horned beast really? This beast in Revelation is an extension of the prophecy in Daniel 7, where four beasts come up out of the sea, so we need to study the prophecy in Daniel 7 in conjunction to know what this beast really is.

[Daniel 7:3~7] And four great beasts came up from the sea, diverse one from anothe The first was like a lion, and had eagle's wings: I beheld till the wings thereof were plucked, and it was lifted up from the earth, and made stand upon the feet as a man, and a man's heart was given to it. And behold another beast, a second, like to a bear, and it raised up itself on one side, and it had three ribs in the mouth of it between the teeth of it: and they said thus unto it, Arise, devour much flesh. After this I beheld, and lo another, like a leopard, which had upon the back of it four wings of a fowl; the beast had also four heads; and dominion was given to it. After this I saw in the night visions, and behold a fourth beast, dreadful and terrible, and strong exceedingly; and it had great iron teeth: it devoured and brake in pieces, and stamped the residue with the feet of it: and it was diverse from all the beasts that were before it; and it had ten horns.

The four beasts that came up out of the sea were a lion, a bear, a four-headed leopard, and a ten-horned beast, whose heads together totaled seven. The last beast had ten horns, so when they were combined into one body, they became the seven-headed, ten-horned entity of Satan. The lion, bear, leopard, and ten-horned beast refer to the ten nations of Babylon, Persia, Greece, Rome, and Rome, but it was angels who actually ruled them. Babylon was ruled by an angel named Lucifer, and the Persian and Hellenic empires were ruled by evil angels called demons.

[Daniel 10:20~21] Then the angel said: Now do you understand why I have come? Soon I must leave to fight against the guardian angel of Persia. Then after I have defeated him, the guardian angel of Greece will attack me.  I will tell you what is written in The Book of Truth. But first, you must realize that no one except Michael, the guardian angel of Israel, is on my side.

Thus, Israel's guardian angel is Michael, and the angel ruling over Babylon, Persia, and Greece is the evil angel depicted as Satan, and Rome and its ten nations were also under their control. The depiction of Satan as seven heads and ten horns is to show Lucifer, who ruled Babylon, and the evil angels who ruled the ten nations of Persia, Greece, Rome, and Rome. They first appeared on earth after being cast out of heaven by the ascension of Jesus, and that is the first little horn.