Revelation 11:7 When they have finished their testimony, the beast that comes up out of the abyss will make war with them, and overcome them and kill them.

Revelation 13:1 And the dragon stood on the sand of the seashore. Then I saw a beast coming up out of the sea, having ten horns and seven heads, and on his horns were ten diadems, and on his heads were blasphemous names.

Revelation 16:14 for they are spirits of demons, performing signs, which go out to the kings of the whole world, to gather them together for the war of the great day of God, the Almighty.

Revelation 16:16 And they gathered them together to the place which in Hebrew is called Har-Magedon.

Revelation 19:11 And I saw heaven opened, and behold, a white horse, and He who sat on it is called Faithful and True, and in righteousness He judges and wages war.

Revelation 19:21 And the rest were killed with the sword which came from the mouth of Him who sat on the horse, and all the birds were filled with their flesh. (NASB ©1995)