You're a vigilante (a person who voluntarily carries out duties usually done by Pro Heroes without paying attention to the law). You're Quirk is Umbra Dominion, which lets you control and create shadows. You use a full-face mask with a voice changer to hide who you are cause being a vigilante isn't really a full-time thing. You're also a student at U.A. high, not a part of the Hero Course. People would know your quirk and put two and two together and figure out you're a vigilante.

But there is this one person you're scared to find out, Katsuki Bakugo, a student in Class 1-A the hero course. The reason why you're worried is cause he's obsessed with both sides of you, the weird Support Course girl that fixes his gear super fast, and Umbra the vigilante. He has no idea yet. You can't let him figure out that your Umbra. You've seen him watch Umbra's fights, your fights, with a dark look in his eyes like he's trying to figure out who Umbra is. And he has the same look when using your gear just with more wonder, and also makes it last longer, you've seen him break Mei's work in 2 or 3 days yours last around 1 or 2 weeks, you two use the same type of materials, and have same building styles. You've asked him about it he just mumbled something, then walked away.

And now, you fucked up big time, in a fight with a villain they cracked you mask that isn't what your panicking about it's the wound it left you now have a big scratch on your face it's every noticeable, and well Katsuki Bakugo, watchs the Umbra's fights a lot many times, he's bound to notice it. And even if you somehow manage to find it for the time it heals the scar is going to be there, and you do have to fix the mask with your free time, which you usual spend on Katsuki's gear if he needs sudden upgrades.

A Week Later

You officially are over, he saw the scratch and your pretty sure he saw the piece of Umbra's mask (The reason why you refer you and Umbra as a different people, is to hide your identity and you change your personality when Umbra). You don't know what to do, you really don't.

A Day Later

You didn't wake up in your dorm... You woke up in Katsuki's dorm. He's gone, so he's most likely in class, Umbra's mask on his desk, your right wrist in bound to his bed frame. You noticed Tapes of Umbra's fights, and beside it, a journal.

You don't know what to do. He was smart enough to turn on every light, so there weren't any shadows, so you couldn't leave through the shadows. And we'll even if you somehow manage to escape. There's a 99% chance people won't believe it.