Some of those who believe that the book of Revelation is future yet to be fulfilled link the "seeds of men" with and Satan and the angels who are cast to earth on the basis of Revelation 12:7-12
And war broke out in heaven: Michael and his angels fought with the dragon; and the dragon and his angels fought, but they did not prevail, nor was a place found for them in heaven any longer. So the great dragon was cast out, that serpent of old, called the Devil and Satan, who deceives the whole world; he was cast to the earth, and his angels were cast out with him.
Then I heard a loud voice saying in heaven, “Now salvation, and strength, and the kingdom of our God, and the power of His Christ have come, for the accuser of our brethren, who accused them before our God day and night, has been cast down. And they overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives to the death. Therefore rejoice, O heavens, and you who dwell in them! Woe to the inhabitants of the earth and the sea! For the devil has come down to you, having great wrath, because he knows that he has a short time.”
This is believed to be of a future fall.
This view is also supported by Revelation 16
And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet. For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame. And he gathered them together into a place called in the Hebrew tongue Armageddon.
So from a futurist literal point of view there will be definitely other beings on earth during this time.....which then concurs with Daniel.
Last but not least pseudepigraphal books such as Enoch mention other entities on the scene during end times:
LVI. 5-8. Last struggle of heathen Powers against Israel.
- And in those days the angels shall return
And hurl themselves to the east upon the Parthians and Medes:
They shall stir up the kings, so that a spirit of unrest shall come upon them,
And they shall rouse them from their thrones,
That they may break forth as lions from their lairs,
And as hungry wolves among their flocks.
- And they shall go up and tread under foot the land of His elect ones, p. 74
[And the land of His elect ones shall be before them a threshing-floor and a highway:]
7 But the city of my righteous shall be a hindrance to their horses.
And 2 Baruch 27:1-14 appears to describe these entities as well:
And He answered and said unto me: 'Into twelve parts is that time divided, and each one of them is reserved for that which is appointed for it. In the first part there shall be the beginning of commotions. And in the second part (there shall be) slayings of the great ones. And in the third part the fall of many by death. And in the fourth part the sending of the sword. And in the fifth part famine and the withholding of rain. And in the sixth part earthquakes and terrors. [Wanting.] And in the eighth part a multitude of specters and attacks of the Shedim. And in the ninth part the fall of fire. And in the tenth part rapine and much oppression. And in the eleventh part wickedness and unchastity. And in the twelfth part confusion from the mingling together of all those things aforesaid. For these parts of that time are reserved, and shall be mingled one with another and minister one to another.
As such, these "seeds of men" appear to be some type of creature strange creature mentioned in the several writings which discuss the end times.