This was inspired by All for Luz by DeathlyJazzHands55
Luz was a normal ten year old with two odd quirks, snatch and Mix. Mix allows Luz to mix quirks together, however they need to be her quirks to mix them. Snatch allows Luz to temporarily take someone's quirk just by looking at them but the quirk will return if the person touches her, there isn't a limit to the amount of quirks she can take and it can't be turned off. Luz is forced to where a special set of sunshades that prevents her snatch quirk from working in order to to prevent any mishaps with people suddenly loosing there quirk.
Luz is chronically bullied by people for both her useless mix quirk and her "villainess" snatch quirk. Luz is always near a teacher at recess both because of the bullying and because the teachers always ask her to use snatch on a kid who's using there quirk and returns it to them at the end of the day in the office (this extends to class as well). Luz still is her eccentric self with her over the top presentations, until one day. Luz was walking home having just seen her mother be pressured into putting Luz in reality check camp.
Luz's thoughts were interrupted by a man wearing a tattered suit and was covered in blood, he spotted Luz an started walking over to her. Luz was frozen in place by her fear as the tall man walked over to her, on the way she felt her shades come off her face and her quirk snatching his except for one which her quirk couldn't grab. The man reached Luz and put his hand to her face and a moment later Luz fell to the ground writhing in pain as the man simply fell over, dead.
After a minute Luz got up not feeling any pain and seen a note in the mans palm, as Luz opened it she was shocked. The note explained that he was all for one and that she was his successor now as well as how his quirk worked. After the initial shock of how all for one worked Luz realized that if she used her mix quirk to mix all for one, snatch and pain nullification she could just look at a person and take there quirk without them noticing that it's gone. So Luz does just that and mixes a pain nullifier quirk, snatch (after using a single use copy quirk to copy it) and all for one together to make a boosted version of all for one that allows Luz to painlessly take/give the quirks of people just by looking at them directly. Luz uses a quirk appraisal quirk and appraises the newly created quirk to see it's downsides. She sees that snatch's downside carried over as well as her eyes will constantly glow a dim golden amber color. Luz quickly put o her shades and continues to walk home.
When Luz got home Camila questioned why she was late and Luz just handed the note from earlier to her. Camila was shocked but was supportive and silently vowed to continue to be so for her. We arrive to the beginning of the owl house's canon where Luz's principle pressures Camila to send Luz to reality check camp. Everything happens as in canon until the first meeting with Eda.
Luz has just taken her book from Eda and tried to go back through the door only for it to fold up and disappear "stay back I have millions of quirks and I'm not afraid to use them!" Luz exclaimed as she turned around "why would I want to fight... A potential costumer" Eda said confusing Luz as Eda led and sat her down on a stool. Eda shows Luz the same stuff as in canon and Luz puts the batteries in the TV. when the guard shows up he says the same thing as in canon but when he grabs Luz her shades fall of causing her to immediately snap her eyes shut and grabs her shades to put them back on. When Eda smacks the guard and grabs Luz her shades fall off again from the sharp movement and Luz quickly grabs them but doesn't close her eyes but instead looks directly at the guard until she can't see him anymore and quickly puts her shades back on.
Eda and Luz arrive at the owl house and after the introduction with king which goes the same as in canon Eda asks Luz a question that's been bothering her ever since Luz first talked "kid, what did you mean by quirks. I've heard humans have developed certain abilities but what did you mean when you said you had millions?" Luz froze at the question letting king which she's been petting get away. After a moment Luz spoke "A quirk grants superhuman abilities and powers to an individual which is genetically manifested when they are at a very young age leading onto adult life. Most of the time a child will manifest either one or two of each parent's quirks based on the compatibility of each parents quirk." Luz explained to Eda's amazement but noticed to Luz's disappointment that Luz hasn't explained the second part of her question.
After a look from Eda Luz continued " I have/received a quirk called All For One. It allows the user to steal Quirks from anyone they touch for personal use or they can transfer the stolen Quirks to anyone. It also allows the user to wield several Quirks simultaneously. Giving and taking away Quirks is done through touch, through a hole in the palm of the user's hand, once it receives contact. I received this quirk from the worlds previous number one villain All for one and all the quirks he stole with it. I was born with 2 quirks, snatch, and mix. Snatch allows me to take anyone's quirk by looking at them in person but they get there quirk back when they touch me and I can't turn it off either hence the shades. Mix allows me to mix any quirks I have permanently, so I can't snatch someone's quirk then mix as it still can be retrieved by the owner. I mixed all for one and snatch as well a pain nullifier as transferring quirks causes extreme pain to the target as well as potential brain death if I transfer more quirks than they can take. This allows me to take anyone's quirk without them knowing at a glance" Luz explained to Eda as she used her magic to copy what Luz has just said into a book.
Seeing this Luz added "surprisingly it even woks for you guys and your magic. I tried it on the guard and it worked" this made Eda pause and contemplate something before brushing it off and the book to continue writing. After a bit and the book to finish writing they all went to the conformatorium where Luz teleported Eda, king and herself to the confiscation room and took the burger queen crown and gave it to king. After Eda explained and warden wrath showed up Luz made sure king or Eda wasn't her sightline before taking off her shades and looking at warden wrath and the rest of his guards before leaving with Eda and king freeing to prisoners as the warden and his guards couldn't do anything to stop it. They make it back to the owl house with Eda and King still hacking up the black sludge that was the byproduct of Luz's teleportation quirk. Luz decided to stay in the isles instead of reality check camp.