I had this idea and I want to see how it goes. (C shown in picture above)

Basically, it's villain C vs All Might, but C's real quirk is revealed when she finally takes off those restricting goggles she's always wearing.

The killer gently wiped off her favorite knife as she walked down the empty street. When she held up the knife to check if there was any blood left, she saw the hero standing behind her. She stopped, not turning around.

"All Might, so nice of you to finally show up. I've been waiting to meet you face to face for a while now..." an evil grin spread across the girl's face as she bowed her head. "They've been sending Class B heroes after me, can you believe it? Finally, I get a really challenge to battle."

All Might's smile almost faltered. This girl before him was responsible for the deaths of pro heroes Endeavor, Hawks, Best Jeanist, Edgeshot, Present Mic, Eraserhead, Midnight, Mt Lady, and plenty more, including some UA students like Mineta Minrou, Shoto Todoroki, Izuku Midoriya, Katsuki Bakugou, Mirio Togata, and half of everyone else.

"You up for a challenge, old man?" Her eyes glowed dangerously. "I'll let you take the first shot, as we both know how this is gonna play out." She held her arms out to the sides as if to embrace someone in front of her that was not there.

In the blink of an eye, All Might had punched the villain right in the back, launching her forward at incredibly high speeds. Her smile widened as she ripped her goggles from her face. A second later, wings were erupting from her back, ones that mimicked the deceased hero Hawks's quirk. She knew bringing the quirks of the people she killed into the fight would anger the #1 hero, and that's just what she wanted. To blind him with rage, so that he can't think right. So at the end of the fight, he'll be seeing red.

The red of his own blood.

The wings pulled her to a stop, her feet that she had extended in front of her barely tapping the building she was about to collide with. Her goggles hang from her hand like a dainty lady would hold an expensive purse. The futuristic material of the gift bestowed upon the Immortal by her friend from the last universe glowed faintly, her memories of the Faded making her smile.

The gift bestowed upon her when she switched from a Beginner to an Immortal flowed through her restricting human veins, practically glowing with power as she used it after eons of waiting. Her head snapped around in a perfect 180°, her body staying unmoving.

"Oh, you gotta try harder than that, All Might. Or should I say, my next victim!" She let out a maniacal screech as her body melted into a puddle of black goop, which started moving towards the hero at incredible speeds.

The goo wrapped around his leg, quickly stretching up his body until it formed back into the villain, her metal encased foot colliding with the heroes jaw, who quickly reacted with a punch to her face.

He stumbled back as she just used the momentum created by the punch to propel her backwards in a backflip, a thin streak of blood flowing down her chin from the bruised corner of her mouth. A snakelike tongue extended from her now reptilian teeth as she formed into another ancient species from universes ago.

What once was a small girl was now a reptilian beast, green scales going all over its body and two great big dragon like wings extending from its back. It roared and lunged forward, ducking under All Might's fist and pushing itself up so it could slash a long gash up the pro's side.

The wound immediately started gushing blood, stinging from the poison that the claws were laced with. The beast smiled and morphed into something new and larger.

A huge dragon creature circled in the sky above the symbol of peace. A large tail lashed down, knocking him far back. The dragon shifted back into the girl, who ran at him, sliding between his legs last second as she pulled a gun from the inside of her jacket, shooting the hero twenty times in the back, ten hitting his heart and ten hitting his weak organs from the long forgotten fight against the now dead #1 villain All for One.

This girl was just great at killing.

The bullets shot directly through the heavily bleeding body of All Might, his heroic form now shifting down to his skeletal body. She smirked evilly and shot a bullet directly through his head, closely followed with two more to make sure he died.

The now lifeless body of the so-called symbol of peace dropped to the ground, the lineage of One for All completely destroyed and the DNA unable to be passed down.

The heroes had fallen, but so had all of the other villains.

Her job was complete, now all she had to do was wait for them all to go to war and kill themselves so this faulty species could be wiped out for all eternity.

She dusted off her hands, putting the gun back where it came from and leaving the scene like nothing happened.

No one can stop her.

She's immortal.