Kaga Tada, the protagonist who desperately saved the world after being summoned in another world as a hero to defeat Schnee, the other hero summoned who wanted to destroy the world.
Though he did defeat Schnee and saved the world, but he was betrayed by the people he trusted as friends and is stabbed to death by a sword.
At that time, he swore:
If there is a next time, he would no longer cling to the word called ‘believe’.
If there is a next time, he would pay them back as cruelly as possible.