Henchman: My Lord, how many portals are you planning to open to this "Human World"?

Neo Storm King: Yes...

Map of all planned entry points to be opened into the Human World as the Start of the New Storm Empire as well as the Pact of Thunder's plot to conquer the Human World and making it their new dominion. How this would be achieved is that the Neo Storm king stole and reverse engineered the mirror leading into the human world. Building new and improved portals that eliminated all the issues and defects of the original portal. Now having the ability to open as many portals as he desires in any place in the Human World and is not tethered to just Canterlot City. Same goes for the numbers of storm creatures: Reverse engineered the mirror pool to establish and build cloning facilities to produce as many storm creatures as he'd like.

The Strategy here is to open up so many portals that it'd be too overwhelming for the human militaries to handle and then through Blitzkrieg, quickly overwhelm and drown said militaries using numerical,magical and even technological superiority. Crushing them near-instantly as well as destroying the leadership of the human nation, effectively preventing nuclear weapons from being used.

Other than shock and awe via the defiling of Iconic human landmarks as well as killing the leadership in the case of portals over capital cities, one of the reasons for the portals to appear over major population centers is so that The Neo Storm King could provide Sombra a supply of captured Humans to press into service in his growing mind control Army. As stated above. Chrysalis would grow her numbers by simply building more hives thanks to feeding off human emotions produced via torture.

This is the beginning of a great interdimensional conflict that would be come to known as "The Storm War" but to humanity, this will be known as the "End War" as this war will see the end of their civilization and their continuity as a species.

The Age of Men is over. The Time of the Storm king has come.

I'm basically following what i'd call the "Darksiders Strategy", which is landing in multiple spots that would be too much for the opponent's military to handle and then attacking immediately, crushing said military almost in an instant: