Just to tell you all ahead of time-it's going to be canon right up until the extended epilogue because my man was supposed to be a hero and that's who he's going to be here. I hope that's ok with everybody.
"CRAP! CRAP! CRAP!" Midoriya followed the scampering platypus through the city, heart in his throat. This was one of his ancestor's magical creatures! If a villain got their hands on it-he couldn't imagine anything worse!
"What the he* is this thing?!"
No, he can. He totally can.
Midoriya gasped in fear as he saw the platypus had jumped on top of none other than his bully, Bakugou, holding onto strands of the boys' blond hair. The two boys he was always with were looking at him with puzzlement.
"Come on, get off!" He took the creature out of Bakugou's arms and hugged him to his chest. The platypus gripped onto Midoriya's uniform, staying flat against his chest.
Bakugou sputtered, "What is that, Deku?!" Midoriya backed away, his hands clutching the animal.
"I-I can't say! It's not your concern!" Bakugou's red eyes widened at the audacity of his voice. Midoriya sighed, "Please, Kacchan. I just want to take him back."
One of the bullies chuckled meanly, "Heh. Pretty brave speaking up at Bakugou. What's a weakling like-?"
Bakugou held up a hand, staring at the creature. Midoriya felt his eyes widen. It looked like Kacchan's heart melted for a minute…
"Don't get used to this, Deku. Go before I change my mind." Midoriya nodded, running off with the creature.
…
After climbing back down in the suitcase (and wasn't that weird to think aloud, much less do?), he placed the creature down. He then climbed back up the ladder to close the lid. Sighing, he climbed down to meet the creature.
"What are you?" He knelt, holding his hand out to it. The creature sniffed it before letting out a purring click and rubbing the top of his head against Midoriya's hand. Midoriya let out a giggle, moving his fingers rhythmically through the downy fur.
He looked toward the books on the desk, interest filling his green eyes. "The journals-of course! I'll look you up!"
He picked up one of the books, opening it eagerly. His green eyes widened in fascination at the different animals and their descriptions (as well as ink-drawn pictures) filled the pages. His grin widened as he found what he was looking for.
"You're a Niffler, huh?" His voice filled with awe as he continued reading, "You are a 'burrowing creature that loves anything shiny'? Your claws look very sharp-I wonder how far you can dig, not to mention thedifferentmaterialsyoucanplowthrough…mutter…mutter…"
The platypus chittered, tilting his head in slight confusion. Midoriya felt his face flush at the look. "Heh, heh…sorry, force of habit."
The Niffler made a noise and crawled up Midoriya's pant leg, up his torso, and settled into his arms, burying his face in his shoulder. Midoriya giggled, hugging the Niffler back.
"Let's see what you can eat, hmm?"