MTL - My Hero Academia: My Personality is the World - Chapter 66

The world changed the day that cracks appeared in the sky– suddenly monsters named『Demonic Beasts』appeared and began to rampage, attacking people.

Meanwhile, girls called『Magical Girls』began to appear to counter the demonic beasts. As they defeated the demonic beasts, gradually people’s lives gained a semblance of composure.

–but when there is light, there is also darkness.

In the corner of an alleyway, a boy who had been attacked by a demonic beast was dying. His voice begging for help did not reach anyone and his body refused to move.

「Boy. Do you want to be saved?」

Looking into the boy’s face, a black cat began to speak to him.

The boy nodded firmly to the devilishly sweet invitation, in response the black cat mocked him.

「Is that so—then I’ll【Haunt (Save)】you」

—on that day, a『Magical Girl』was born in a place that no-one knew.

『She』never laments, no matter what the future may bring.

In this fantasy world, music and aether rules all. However, there is constant threat of demons and natural catastrophes. The most powerful men are musicians who use music, alchemy, and spells to safeguard their homes. A young man who just wants to find his father and know why his family was exiled, starts his journey of becoming musician – a journey that leads him to the crown of justice and glory.We are born of aether, grow under aether and die as aether. Awe of Aether! – Holy Code.

A chance to change, to challenge destiny, making dreams a reality, and live a legend! A regular man gains a system that allows him to turn into a fish!

- Description from Novelupdates