Auther: The main thing I'm changing is this isn't going to be a crossover with xxxHolic as I thought that, that derailed the story to focusing more on xxxHolic and magic/fairfolk as a whole instead of what should of been the main focus. Izuku being a Cardcaptor.
Izuku's life of the first day of school in September, was turned from bad to worse when his idol. All Might told Izuku he couldn't be a hero. So, there he was in the library where he usually was in the afternoon. Only this time he was crying out of sadness instead of reading a book and being happy, that was until one of the librarians (Ms. Fuji) came up to him and brought him to the back room and told him to pick and keep one item. He decided to keep a suitcase (hoping it and what was inside counted as one item, he was right) hoping something in it would bring him joy, only when he got home. He discovered in it were some old clothes, what looked like a tiny staff and a card-carrying case with some cool cards in it. He picked up the first one (Wood) while examining the one below it (Windy) and said "Windy, what does that..." Only to be interrupted when a gust of wind blew through the house and toke all the cards in the card-carrier with it, leaving him with only the card in his hand.
He was only toke out of his stupor when a winged animal (Cerberus/Kero) came from the card-carrier and said "Good morning, human." "Actually, it's night. Who are you and what was that gust of wind that blew all the cards away?" Izuku asked, only for Cerberus/Kero to say "I'm Cerberus but you can call me Kero and that gust of wind that, wait WHAT!?" "I said..." Izuku said only to get interrupted by Kero who said "I know what you said, I just can't believe this is happening again." "Again?" Izuku said, only for Kero to say "Yes, again with my second to last holder Sakura. I thought you were smarter than that, like my last holder. Card Show." "Ow, I know of Card Show and her pet Cerberus. You must be him but you look so different, hey can you get me her autograph. She's kind've my favorite magical themed hero, did you know it's been exactly fifteen years since she was last seen and yet people still don't know of her real identity." Izuku said, only for Kero to say "Wow, has it been that long since I've seen her. I wonder how her and her husband are doing with trying to have a child which is why she quiet and I'm getting off track, I need a cardcaptor and that Mr. is you (while pointing at Izuku)." "Me (while pointing at himself), I guess that's fair given I was the one who lost them in the first place. Which I still don't know how." Izuku said, only for Kero to say "You did it by invoking the card's magical power." "Yah right, magic is real." Izuku said, only for Kero to say "Weren't superpowers and superheroes thought of just the same way?" "Yah but that's different." Izuku said, only for Kero to say "Different how, like how can you explain what just happened without magic being involved." "Um, er..." Izuku was interrupted by Kero saying "Exactly, this is magic. Just like how the cards are magic and have been changed into elemental creatures that need to be captured and returned to their card state." "Wait, WHAT!? You expect me to defeat beings with the elements on their side, are you crazy!?" Izuku almost shouted, only for Kero to say "Actually, each creature has only one element on their side but other than that. Yes, I do (Izuku starts to walk away). Wait, you have me with the element of the sun. Of course, I can't access that in this form or that form for the matter (Izuku starts to leave again) but you'll have these magic clothes which become any one and only one clothes you want and do one and only one spell on you while you're wearing it." "Then I guess the spell while be hiding my identity as I'll kind've need it as I'll be breaking the law of vigilancy by doing this." Izuku said angerly, only for Kero to say "Mr. umm..." Only for Izuku to interrupt with "Izuku, the names Izuku Midoriya." "Ah, Izuku. Well, Izuku do you care more about the law or about saving someone because these creatures will put people in peril." Kero said, honestly Izuku didn't think about the trouble these creatures would bring and he did care more about saving people than the laws feelings but there were still heroes who could deal with it. Izuku was on the fence when Kero turned on the news and Izuku saw Katsuki in the arms(?) of the slime creature from earlier with no one doing anything about it. That's when he knew he had to do something about it. He put on the clothes and they transformed into a green hat that had a pair of green with white inside them bunny ears on the hat also on the hat were stars and on the hat's white-ribbon thingy was a white moon on it and the hat, green robes also with stars on them with a green bunny's tail on the back, the robes were tied with a white ribbon, underneath the robe was a white long-sleeved shirt, green gloves, white pants, and green shoes. Izuku would've taken in his looks more and just the fact he had bunny parts as part of the costume if he had more time and he was about to leave when Kero said "Wait, you almost forgot about this (holds up the tiny staff). You'll need it to capture the cards if and when you encounter them and to invoke their power, say "Key which hides the powers of the dark, Reveal your true form before me. I, Izuku Midoriya command you under our contract Release!" To turn it to normal size and to get the card back into card form say "Return to the form that you were meant to be in! SAKURA CARD!" And to use a card say "Creation of Clow, lend your power to my key, Bestow the magic of the card unto my key!" Then say the name of the card and then what you want it to do." Izuku was about to fire back that he still wasn't going to capture these cards for Kero but Izuku was running out of time, so he didn't and instead ran out the window (didn't want his mother finding out about his vigilantncy after all) and to the scene of the crime with him saying "Creation of Clow, Lend your power to my key, Bestow the magic of the card unto my key! Wood, Make Me Go Fast." That made a burst of wood come from the floor under his feet with his every step, making him go faster than before.
When he approached the crime scene, he made the spell stop and went through the barricade and said "Creation of Clow, lend your power to my key, Bestow the magic of the card unto my key! Wood, Save Katsuki!" This caused a branch with claws at the start to burst out of the ground and heads toward the slime monster who retaliated with a fire ball but the branch just weaved out of the way and it's jaw like claws snapped around Katsuki and retreated back into the ground it came from pulling Katsuki from the slime monster. The slime monster was about to retaliate when All Might himself came from the shadows and punched the air. Destroying the slime monster and creating a rain shower that destroyed the flames. Everybody flocked to All Might while Izuku quietly walked away with one reporter asking him "Wait, who are you?" "I'm (looks at his reflection) Moon Rabbit." He then leaves on a tree he created with the card. He took off the outfit just to make sure he wasn't followed home where he snuck back in through the window.
Once home Kero congratulated Izuku with Kero saying "You did wonderful today, I can't wait to see what you'll do against a card." "I'm still not sure about that." Izuku said honestly, only for Kero to say "What about today?" "Today was because no hero was going to do anything or/and could do anything against the monster." Izuku pointed out, only for Kero to say "And what if those circumstances happen during a card attack." "I don't know what I'll do then." Izuku said weakly, only for Kero to say "I can work with that."