Her tears were floods,
Her rage was earthquakes,
Her panting was hurricanes,
Her heartache was a forest fire,
And her Love was remedying moonlight.
She was the Universe, and the Universe was Her.

-Mustafa Tattan

(Going to head in an AU direction. I might jump back to the mangas pov, don't know yet but I hope that you like where this leads)

The moment they appeared, Sirius's senses were going wild. Taking a stand in front of her students as the League Of Villains appeared. She had heard they did this once before but she didn't think they'd go again. She growled at them, her tails covering the students as she and the teachers stood ready to fight. Fight to protect the children. Ready to die for them.

"I see a new face, I wonder who you are?" Tomura said looking at Sirius, eyeing her with a sickening smile on his face. Father was covering his face but she could sense the smile. She let out a growl, warning him to stay away from her children. "Let's test out the new Nomu. Have fun, High End."

~Sirius POV~

I've heard about the Nomus, mostly everyone giving me warnings. Saying that the newer ones are faster and stronger than the previous ones. I can't blink or I'll be killed. Looking back at the students. It was mostly of class 1-B that were scared but class 1-A was ready for a fight. No, I can't let them fight. They have suffered enough at the hands of the League, no more.

The fight began, the students were forced back. Aizawa was busy fighting Tomura while I was fighting High End. He was fast, faster than most people I've fought but not fast enough. My parents may have taught me to contain my powers but they didn't want me living life defenseless. So they taught me how to fight in many different ways. Hand to hand, Muay Thai, BJJ, and other fighting styles. It came in handy for many fights, this one was the most important fight. Even with my knowledge, I was still not much of a match. I could pass my quirk to him, but I didn't know if it would work on something like him.

Somehow I was sent flying from a hit that I couldn't dodge, he was even tougher than I thought. I ended up crashing landing into a building with High End right behind me. The building I had crash-landed on just so happen to have Endeavor and Hawks inside it. Lucky for me, I landed on Endeavor so no citizen got any major injuries. With the help of two pro heroes, High End was defeated. But Endeavor also received a bad facial injury. He was taken to the hospital while I rushed back to my students, once I was returned anger rushed through me. The Pros were getting beaten to the ground and some of the students were hurt. Something in me was beginning to hurt, burning within. My parents' voices began echoing in my head, voices telling me to run and don't stop.

"No...More." My body started changing. Hound Dogs words echoed in my head. No more holding it all in. No more hiding my true self. If the students and staff fear me afterward, then. "That's fine by me." My body started crumbling away revealing my true form, all jaws dropped at the sight. My form made it appear as if the night sky was walking around during daylight hours. I dared my fangs at the League, showing them I wasn't messing around. My large fox form stood over everyone, shielding them from the League's eyes. Lowering my head near Vlad's face, blood dripping down the side of his head. His breathing was irregular, he might have taken a hit to the chest.

"I'm going to let loose and when I say that, don't take it lightly. Move everyone as far away as you can get them. This is going to be big." Vlad nodded his head, shouting to everyone to fall back. Someone grabbed Bakugo before he could run headfirst into the fight like he always did.

"Hell no, let me fight them!" He froze the moment he met my eyes. The glowing blaze filled my eyes, giving him a warning.

"Get out of here. Now."

A big fight broke out between me and the League. It was mainly me vs some of the lackeys. The main guys kept back, it wasn't until Tomura used his quirk, disintegrating the ground. Aiming at the remaining students and staff, who were helping anyone left. Using my Nova Roar to block off most of the attack but the force of the blowback caused everyone to be pushed back.
Upon seeing my students, my children laying on the ground injured because of something that I caused. Something in me snapped. This has gone on long enough. They have pissed off the wrong woman and I'll make them regret it.