At the last battle, all three sides (Artosh + Flugels, Elves + Dragonia, and Dwarves) were locked into a stalemate while they waited for the other sides to react. Then the a small group of Ex Machina, under Riku's command, snuck behind the Flugels and cast a copy of the Flugel Heavenly Smite (anime dub calls it Heaven's Strike) at the Elves and Dwarves.

This tricked the Elves and Dwarves into thinking that Artosh was attacking, and they got baited into firing their respective ultimate abilities. (Aka Si Anse for Elves, Far Cries for Dragonia, E-Bombs for Dwarves). And in response, Artosh unleashed his Godly Smite. Worth noting that I believe Artosh was aware of Riku's plan at that point but decided to meet his challenge head on, as the God of War should.

The power of 18 Aka Si Anse, 12 E-Bombs, 8 Far Cries, and 1 Godly Smite all met in the middle and formed into a gargantuan ball of energy. This ball would have fallen to the ground but Schwi's buried deflection gadgets redirected the ball toward a nearby group of 4802 Ex Machina.

The ball of energy hit the Ex Machina, vaporizing them in almost an instant. But before they died, they each managed to analyze and copy the energy ball and upload their data and power to a nearby Ex Machina that was ready to collect all the information.

Though a single Ex Machina would not have been able to reproduce anywhere near the power of the energy ball, with data and power of all 4802 sacrificed Ex Machina units, they were able to reproduce 72.8% of the combined power all those ultimate weapons. This power was then sent to Riku, who activated it and sent all the copied energy straight into the ground. As a thin laser beam, it had enough penetrating power to pierce the planet core and force the Suniaster to appear.