Exploits from Another World

Isekai. The genre of medieval magic, and adventures. The home of clichés, that appear in all works of it.
13-Year-Old, Riamu Narrcamu, a narcissistic realist. Finds himself teleported to another world, along with not only his class. But his whole school as well!
Greeted by a princess upon arrival. The school is tasked with saving the world of Ingtasia, from the "Oh, so mean" Demon Lord.
Similar to every Isekai story Riamu has read. He doesn't seem up for the task oh having to fight for an unknown world when he wasn't even willing to fight for his home world.
But to his "surprise", his stats and abilities which read "???" Don't seem up for the task either.
Fleeing from the outraged princess, along with four other people with the unknown abilities. They run far away from the school. "Never to be seen again."
All they want to do is to be able to live at the very least. And maybe experience some joys the world had to offer. But the taboo ability in their way... Is making living back on Earth much more enjoyable!
"Maybe there are some holes in the system we can EXPLOIT."