Acts 5v27
Revelation 16 tells of the kings of the earth being assembled for the great day, to the place called Har-Mageddon. The actual battle is recorded in 17:14 where they fight the Christ, but because he is in overall authority in the earth he will defeat them. The slaughter is not just because the Heavens want to slaughter someone, but to overcome an active and determined rebellion - not doubters.
I looked up the reference Rev 17v14. Armageddon seems to involve 10 kings. Who are the 10 kings?