I admired heroes but became a villain

In this world, there exists an evil organization that travels through the fantasy world and destroys its future.
There are also heroes who fight against such evil organizations. After signing a contract with the mascot, they can become magical girls who fly in the sky, shake the earth, and fight for all the beauty in the world.
Guo Linglong, who admired these heroes, always believed that this was a world isolated from him as a man, until one day, a black mascot broke into his world and invited him to a contract.
Fight side by side with the cold, handsome, cute and pretty magical girls on the same battlefield...
Looking at the magical girls in front of them, some of whom were trembling with fear, Guo Linglong rubbed her temples with a headache.
Where on earth did this go wrong?