The army of 'two hundred million horsemen'
that follows these angels, are either humans
or they are of the spirit world.

"And the number of the army of the horsemen
were two hundred thousand thousand: and I
heard the number of them." Revelation 9:16

These have to be spirit-horsemen. An army of
200,000,000 horsemen would be more than
the natural resources of the world.

Even if it is conceivable that an army of this
size could be mobilized, there certainly isn't
that many horses available.