You Want Me to Be a Hero? Sorry, I’m No God!

[No System + invincible protagonist + transformation + supernatural powers + heroes + one heroine + battles + high-martial-arts fantasy]

The 21st century of the cosmos:

As human technology advanced at an astonishing pace, invasions by strange creatures resembling the nonhuman beings of myth and legend began appearing all over the world, accompanied by rifts in space.

Among these invaders were merfolk with human upper bodies and fish tails (though some had human legs), as well as winged birdmen, or angels, who differed somewhat from their mythical counterparts and were somehow carrying all kinds of high-tech equipment. There were also monsters whose very appearance could trigger an instinctive fear in any living creature...

Humanity suffered devastating losses in this war to defend the cosmos. At this critical juncture, after losing most of its territory and population, humanity finally found a turning point: people with extraordinary abilities began to emerge. Rallying under their banner, humanity sounded the charge to counterattack the invading monsters.

Yet even with humanity’s desperate resistance, only a small portion of the lost territory was reclaimed. And the emergence of these ability users caused crime rates around the world to skyrocket. Some arrogant ability users even carved out territories for themselves, using their powers to force the weak into submission and splitting most human cities into separate domains ruled by those with special abilities.

Amid all manner of crises and despair, the first true superhero in human history was born!