In the book of Daniel, Satan is described as a little horn. The little horn is prophesied to kill and harass God's people, force them to worship idols, and oppose God. However, the evidence shows that the little horn (Satan) appears not once, but twice.

[Daniel 7:7~25] 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.I considered the horns, and, behold, there came up among them another little horn, ...(25) And he shall speak great words against the most High, and shall wear out the saints of the most High, and think to change times and laws: and they shall be given into his hand until a time and times and the dividing of time.

[Daniel 8:8~25] After this, the goat became even more powerful. But at the peak of his power, his mighty horn was broken, and four other mighty horns took its place--one pointing to the north and one to the east, one to the south and one to the west.  A little horn came from one of these,...(23) When these rulers have become as evil as possible, their power will end, and then a king who is dangerous and cannot be trusted will appear.  He will gain strength, but not on his own, and he will cause terrible destruction. He will wipe out powerful leaders and God's people as well.  His deceitful lies will make him so successful, that he will think he is really great. Suddenly he will kill many people, and he will even attack God, the Supreme Ruler. But God will crush him!

The first little horn appears in the midst of the ten horns and the second little horn appears in the midst of the four horns, which foretells the appearance of Satan after the ten Roman nations, and the second little horn foretells the appearance of Satan after the four nations that split off from Hellas. However, God refers to the end of the age as the time when the second little horn appears, not the first. Therefore, the first little horn prophesied of Satan appearing in the middle age, and the second little horn prophesied of Satan appearing in the last age.

[Daniel 10:14] Now I am come to make thee understand what shall befall thy people in the latter days: for yet the vision is for many days.

[Daniel 12:9] And he said, Go thy way, Daniel: for the words are closed up and sealed till the time of the end.