Angry Birds X is a series that takes place after the battle in the Magma World.
The Extinctionerex was ready to destroy the Bird's homeland and the Pigs had their routine to control it to destroy the eggs.
The birds take off to kill the pigs and destroy the Extinctionerex.
Meanwhile the Boomerang Bird notices a red laser coming toward the birds and the ship crashes into the Pig's fort making the Birds madder that they used machine guns and artillery-type weapons.
The Pigs are dead and they destroy the place falling into the Earth back to where they were with the eggs.
They returned to being free making there victory.