Seven great gates appeared on Earth.
Demons, angels, dragons, and other mysterious creatures appeared on Earth.
Caught off guard, humanity suffered losses, but still managed to stop the invasion.
A year later, humanity launched a counterattack into another world.
This world was home to all kinds of strange powers: colossal fortress cities, dragons hundreds of meters long, and Chosen Ones whose bodies could withstand missiles.
But against steel treads, it was all for nothing.
"Hello? Is this the Apocalypse Tank Armored Division? Yes, it's me. That's right, I see a Greater Demon among the enemy forces. Open fire on all of them! Keep firing! Turn them into scrap metal!"
"Peacekeeping Air Force? We've spotted a large enemy force ahead, with a sizable air contingent. Take control of the skies, then carpet-bomb them!"
"What? A meteor wiped out an entire division? Damn it! Second Army Commander! Get my vacuum implosion bomb ready!"
