Near the end of the 7 years, in Daniel 11:40-44, the beast-king headquartered in Jerusalem will be attacked from the south, then north, then east.
Why ? We can only speculate. imo, it will be because the beast-king (king of the West, i.e the EU with likely allies of Canada and the United States) will be directing all the middle east oil to the western alliance. Oil being the life blood of the nations, will give them no choice but to attack the beast-king to free up the oil.
It should be noted that the attack from the east will be by the armies of China (Revelation 16:12). In Revelation 9:13-19, there will be a third of mankind killed by a 200,000,000 size army. So I think that will be by the armies of China as they march westward through Pakistan, India. Afghanistan, Iran, Iraq, and other "stan" countries.
So there will be a big battle near the end of the 7 years, Daniel 11:40-44.
As the battle is taking place, like a thief in the night, the sixth seal event will happen and the world will see Jesus in heaven, sickle in hand.
In the face of the threat to their existence, the nations will stop battling with the beast king and his armies, and will unite under the beast-king's leadership (Revelation 16:12-16). And with their armies already in the middle east will gather at Armageddon to prepare for making war on Jesus and His army of heaven.
This is a mess.
The battle taking place in Rev 9:13-21 (at the start of the 6th Trumpet) has nothing to do with the 6th Bowl war (Armageddon).
The reference to the 200 million army is a reference to the chariots of God in Psalm 68:17's 'tens of thousands, thousands' (2 tens times 10000 times 10000) (2 x 10,000 x 10,000= 200,000,000).
40At the time of the end, the king of the South will engage him in battle,
i but the king of the North will storm out against him with chariots, horsemen, and many ships, invading many countries and sweeping through them like a flood.
41He will also invade the Beautiful Land, and many countries will fall. But these will be delivered from his hand: Edom, Moab, and the leaders of the Ammonites.
42He will extend his power over many countries, and not even the land of Egypt will escape.
43He will gain control of the treasures of gold and silver and over all the riches of Egypt, and the Libyans and Cushites
j will also submit to him.
44But news from the east and the north will alarm him, and he will go out with great fury to destroy many and devote them to destruction.
k 45He will pitch his royal tabernacle between the sea and the beautiful holy mountain, but he will meet his end with no one to help him.
You say that the 'beast king' will be headquartered in Jerusalem, but it says that he invades the 'Beautiful Land' in verse 41. Why is he invading the Beautiful Land (which means the land of Israel) if he is already headquartered there? Answer: he's not headquartered there.
Verses 36-45 have a double meaning: both the Dan 7 Little Horn & the Dan 8 Little Horn.
41He will also invade the Beautiful Land, and many countries will fall. But these will be delivered from his hand: Edom, Moab, and the leaders of the Ammonites.
In the first meaning the Dan 8 Little Horn (the Assyrian) is invading Israel, but the Dan 7 Little Horn (ruler of Tyre) saves/ plucks up Edom, Moab, Ammon. That is what is meant in Dan 7:8's plucking up 3 horns by the Dan 7 Little Horn.
The Psalm 83 coalition is comprised of 10 horns, among which are Edom, Moab, Ammon. (Also includes, Tyre and Assyria).
The Dan 7 Little Horn is the angel that is swearing an oath to heaven in Dan 12:7 - this is the same angel as the Rev 10 mighty angel.
45He will pitch his royal tabernacle between the sea and the beautiful holy mountain, but he will meet his end with no one to help him.
Why does this verse mean?
The Assyrian will pitch his 'tents'/'tabernacle' when his people 'destroy the city and sanctuary' in Dan 9:26.
Tyre will rescue Edom, Ammon, Moab from the Assyrian so as to fulfill Isaiah 11:1-14. Tyre, the Dan 7 Little Horn will confirm the covenant of Dan 9:27 by 'swearing an oath to heaven'. For the first half of the covenant, this is the time of Dan 7:25 and the 1260 days of the 2 witnesses.
Just read Dan 11 and 12 straight through, the abomination idol of Dan 11:31 will be during Dan 9:26 during the start of the 6th Trumpet (Rev 9:13-21). When Tyre 'rescues' Israel, he will confirm the covenant in Rev 10:5 becoming the 'branch' of Isaiah 11:1 who takes over Edom, Moab, and Ammon (Isaiah 11:14)
He will be the 'Branch who will build the temple' (Zech 6:12-15) thus giving us the double meaning in Dan 11:45 'pitching royal tabernacle'.
But Tyre will be the 'wicked Branch' of Isa 14.