Katsuki has always known what he truly wanted for a very long time. Even from the ripe young age of four years old, Katsuki Bakugou, knew that he wanted to make Deku his and only his forever. Izuku looked up from playing in the sandbox and smiled brightly, "Do you want to help me build a castle, Kacchan?" It was that smile that made young Katsuki's chest feel weird with something that he wasn't able to describe quite yet. It was the way that the idiotic Deku looked up to him with fierce admiration because he had a strong quirk, that made him want Deku to only look at him that way and no one else. Katsuki was always a brilliant child ahead of his time, he had gotten his quirk before anyone else in his pre-school class. He also knew that the bite mark was the way everyone else would know that Deku was his and only his. He had seen it on TV many times from the shows his mother liked to watch. Katsuki was also the type to get what he wanted when he wanted. His tiny body moved with fierce precision as he tackled Izuku in the sandbox at the park they were playing at. Once he had him where he wanted, Katsuki bit down on the one soft spot on Izuku's neck where his smell was strongest.

Inko and Mitsuki were both instantly alerted by the sounds of screaming coming from the area their children were playing at. They were both shocked still at the scene before them. Young Bakugou had Izuku pinned in the sandbox while he bit him, causing poor Izuku to scream in pain with tears welling from his emerald green eyes. Mitsuki moved first and yanked her demon spawn from on top of the smaller boy. Katsuki snarled and bit at her, but she bear hugged him into being still, even though he remained struggling. Inko went to Izuku's aid to inspect the damage Katsuki had done. She gasped when she saw the spot Katsuki had bitten, he had claimed Izuku. Inko pursed her lips in a tight frown, before schooling her face to comfort Izuku.

"I-it was an accident, Kacchan didn't mean it," Izuku sniffled as he wiped away his tears. Katsuki huffed, of course, Izuku would defend him to keep him from getting in trouble they were best friends after all. Mitsuki smacked the demon upside the head while she too turned her attention to the smaller boy. There, clear as day on the young boy's scent gland was the bite mark Katsuki left. She smacked Katsuki upside the head again, the little fucker actually went out and claimed Izuku before they even presented. Mitsuki wasn't exactly quite sure where to go from there. Marking was typically followed by mating but the two were far too young to even know about that kind of stuff. As such, the claim was incomplete, but the mark remained to ward off any others who would try to make a claim later in the future. Meaning, Izuku's chances at finding an actual mate in the future were drastically reduced.

"What do you think, Inko? Will it scar?" Inko perked up at the sound of her name and sighed softly, "I'm not sure, but it looks like a definite possibility." Mitsuki groaned, leave it to her to take her eyes off of her demon spawn for a few seconds to chat with her friend, for him to go and pull shit like this. Inko tenderly wiped away the blood on her child's neck with a handkerchief while he sniffled softly.

"Katsuki, what do you say?" Katsuki looked down at his friend who was getting tended to by his mother. He was still being held in a bear hug, by his own mother. He wasn't exactly sure why he had to apologize, he'd seen people do the same thing on the TV shows his mom watched all the time while she cooked dinner. It was how they made sure that person belonged to them, right? Still, Deku was crying like it hurt really badly, and that he did feel bad about. Katsuki sulked as he looked the other way, "I'm s-sorry, stupid Deku." Mitsuki sighed unsure of where she went wrong for him to turn out to be such a brat.

"I'm going to take him to see a doctor this week because I'm worried that Izuku-kun is slightly behind in growth right now. I'll ask what we should do about this current," she paused and looked down at the bite mark, "predicament." Mitsuki nodded at her friend, "Give me a call after you find out what to do. For now I think these kids should go home." Izuku sniffled lightly, he didn't want to go home yet. He didn't even to get to build the castle with Kacchan like he wanted. But he didn't want Kacchan to get in any more trouble either. Izuku pouted as he was lifted to his feet by his mother, "B-bye Kacchan, I'll see you later." He waved towards the ash blonde who could only huff in reply. Mitsuki sighed, how the hell was she going to survive another fourteen years with this demon. She put the red-eyed boy down after the Midoriya's were a good ways away, "What in the world was all that about? Why did you bite poor Izuku-kun suddenly?" Katsuki glared at her with a face that would eventually put fear in even the toughest villain's heart, "I wanted to."

"Well, explain it to your father after you get a spanking for what you did young man! You might have just ruined that boy's future!" Katsuki huffed and put his hands in his pocket grumpily. Mitsuki groaned internally, not sure where the boy got all of his attitude from. "You're just lucky I'm having your father do it, I would give you multiple," she threatened. She grabbed the young boy's hand and sighed heavily, "What do you want for dinner tonight?" Katsuki paused as he trailed slowly alongside his mother, "Curry."

...A week later…

"I'm very sorry to hear that, Inko. Just let me know what we can do to make it up to you," Mitsuki whispered softly. Inko was a mess as she quickly peeked over at the boy who was currently watching a rerun of the All Might movie he loved. She had taken her son to see the doctor about Izuku's stunted growth, only to find out he was quirkless, and that on top of that Katsuki's mark would indeed scar, even though the claim wasn't actually completed. Izuku would be ruined if he presented as an omega, because he would be unable to find any suitable mates. She could only pray that he presented as a beta like herself and her late husband.

"My husband owned a little house in the country that he inherited from his mother. I think right now that Izuku-kun and I will take a little trip up there. I'm sorry Mitsuki-chan, but I don't know when I'll be back."

Mitsuki swallowed the lump in her throat, Katsuki was not going to react well to this news at all. She readjusted the phone on her shoulder as she stirred the food she was cooking in the pan, "I understand, Inko-san. Well keep in touch, I could always use fresh persimmons, and I hear they grow really well out in the country." Inko nodded in affirmation, even though she knew that Mitsuki-chan couldn't actually see her, "Thank you for being so understanding." At that Inko hung up the phone and turned her attention to the boy who was a shell of his usual self.

"Mom, do you think I can be like All Might someday?" Tears flooded her eyes and she wrapped her arms around the small boy, "I'm sorry Izuku-kun!" Izuku's world came crashing down, his dream of being a top hero like All Might were ruined. He was in the minority of people who were born without quirks. How was he ever going to be able to face Kacchan with the way he is? Inko only squeezed her son harder at his lack of response, "Izuku-kun, we're going to go away for a little while ok? Things will be better over there." Izuku couldn't even reply as his world crumbled beneath his feet.

…Meanwhile in the Bakugou household…

Katsuki was in a sour mood and he had no idea why. He had a worrying feeling that something happened to the idiot Deku. Not even playing with his remote control racecar was making him happy.

"Mom?" Mitsuki looked over from the kitchen to where Katsuki was splayed out in the living room, "Yes?"

"What's happening? I don't feel well, but I don't feel sick." Mitsuki lowered the flame on her stove and went to feel her child's forehead, "Well, you don't feel feverish. What's wrong honey?" Katsuki shrugged, he didn't know, that's why he asked. "When can I play with Deku? I haven't seen him." Mitsuki frowned, perhaps the claim was deeper than they thought. No, that wasn't possible they were only four years old.

"I'm not sure honey, the Midoriya's are going on vacation for a while, okay? Inko-san got some worrying news today about Izuku-kun." Katsuki frowned and put the controller to the car down, "What's wrong with Deku?" Mitsuki gave him a soft smile that did not match the rest of her face, "Well, Izuku-kun is a little different is all. He doesn't have a quirk." Katsuki rolled his eyes, he didn't see why that was a big deal. After all, if anything ever happened he would be there to protect him. Katsuki himself had just started to have his quirk manifest and was able to make small sparks from his hands. He's always been told he has a strong quirk so it wasn't a big deal if Izuku didn't have one.

"When are they going to get back from vacation? I want to show Izuku my new racecar." Mitsuki was shocked by how little Katsuki reacted, but she supposed that type of thing didn't effect four-year-olds as much. She stood up and went to check on her food, "I'm not sure honey, I'll let you know as soon as I know." Katsuki huffed, hoping that the stupid Deku wouldn't be gone too long so they could race against each other. Except, that it was years before the Midoriya's came back to the house next door.