Izuku placed the miniature version of the miracle box upon his desk, Nezu had instructed him not to open it until he was home. Sliding into his desk chair, Izuku flipped the lid open, revealing the purple brooch within. He cautiously reached out, then quickly pulled his hand away as the pin exploded with light.

The purple light gathered into a ball in front of him, from which came a creature. Izuku presumed it was the Peacock's Kwami, though this one's appearance differed greatly from Mullo. It's body was a phthalo blue, the sclerae of its eyes a much deeper blue. From its lower back came five feathers, each one larger than the rest of its body. It spoke in a high pitched voice, flying around excitedly as it spoke: "Hi! I'm Duusu, you must be the holder Nezu told me about!"

Izuku took a few moments to catch up with what the creature had said, before responding: "Izuku Midoriya, I suppose I am."

"That's a brilliant name master. Now, I suppose you want to know about my powers."

"Just Izuku is fine and I don't really have any idea what I'm doing."

"That's fine, it's not every day you get a Miraculous. As you've seen with Nezu, a Miraculous allows you to take on another form, and gain powers when you do. The transformation phrases for me are 'spread my feathers' and 'fall my feathers'. Once you do that, you'll have enhanced strength and speed, along with access to my main power, Amokization."

Izuku mumbled what the Kwami had been saying, his urge to reach for a notebook ever increasing. "Amokization is the power to create a Senti-monster, a creature or object formed from emotions. To do so, pluck a feather from your weapon, and imbue it with your emotions, it's easy once you try it. That feather, now an amok, is placed inside an object related to the emotion it was formed from. That object is then capable of controlling the result in Senti-monster."

Izuku was now rubbing his temples, attempting to take in the barrage of information: "I feel like this will be easier if I try it out, if that's ok?"

"Perfectly fine m- Izuku!"

After stopping to buy almonds at Duusu's request, Izuku found himself standing within a forest's clearing. "Ok. So all I have to do is... Duusu spread my feathers." The Kwami was converted into a ball of light, which flew into the brooch, then covered Izuku's body.

When the strange feeling and light faded, Izuku found himself within a new outfit. He ran over to a small pool within the clearing, the reflection giving him a good look at his new appearance. His skin was now a light purple, his hair slightly darkening as well. Contrasting the rest of his face, Izuku's eyes seemed even brighter than before, the green illuminating his features. From his ears, came two peacock feathers, their shape curving upwards, mirroring that of All Might's hair.

The suit he wore was cloth, predominately a purple, with blue lines running down its sides. Upon his hands were loose gloves that went to his elbows, they were mainly blue, with two purple lines near the bottom. His joints were covered with blue protective pads, and his feet were covered with recoloured versions of his normal footwear.

He looked down to his hip, on which was a hand fan, the top covered in feathers. Plucking one of the feathers and retrieving a notebook from his bag, he concentrated on the curiosity within him, channeling it into the feather. The words he spoke came naturally to him, likely a result of the magic he wielded: "Come my Amok, bring my creation to life."

The feather was placed against the notebook, melting into it. Izuku raised his hand, a purple matter forming inside, shaping with his will. When he was finished, a pair of binoculars landed within his grasp. Looking through them, a voice whispered the names of everything he observed. "It worked! Focusing on my curiosity allowed me to form something that satisfies curiosity. Therefore if placed against something like anger then..." The teen descended into endless muttering, only stopping after five minutes, when the magic around him faded, releasing Duusu from the Miraculous.

A few days later, two figures sat upon a rooftop, observing the warehouse across from them. One spoke up, they were dressed in a skintight suit, their most notable feature being the hands that replaced their feet: "Good job tracking these guys down, that warp quirk has been annoying."

"Wait... I see movement." The other spoke, this one was dressed in bulkier armour, one arm ending in a thin tube. "They're here, but whoever they're dealing too seems to have bailed. I'll take the front, you take the back."

"Got it." The other figure jumped away, leaving their partner to approach the warehouse doors.

Izuku's pencil was dropped back into his bag, the homework he had finished following it. He turned his chair to address Duusu, but was forced to stop has a foreign feeling in his mind caused him to fall to the ground, his Miraculous heating up against his chest. "Duusu! What's this?"

"It's a powerful emotion, the Peacock allows you to feel the emotions of people in order to help create Senti-monsters. This is what despair feels like, it's prob-" Duusu stopped, then dashed to the Miraculous. "It's Kaalki!"

"Who?"

"Kaalki, the Kwami of the horse Miraculous, I can sense her. She's near someone who's in despair. I think we should help them! If we do, we might be able to find the horse!"

"B-but, should I just use the Miraculous without Nezu's permission."

"It'll be fine, now transform."

A grunt of pain echoed through the warehouse as the heroes were thrown across the room, the humanoid panther they were fighting towering over them. "You punks never stood a chance against me, though I ain't stupid enough to kill some heroes. Me and my guys will be leaving, see you around. Kaalki, full gallop." The man gained a horse themed outfit, and prepared to leave.

The hero within the bulky armour attempted to stand, but was interrupted as a purple feather descended onto their helmet, and a voice echoed through their mind: "Photon, I am Inutile, I have the power to save you from this despair, I present to you, Fetch, with him, this villains power will be taken away."

In front of the hero, formed a dog like creature, though this appeared to be made of marble. Photon felt her helmet vanish, at the same time, the dog leapt forwards, tearing the glasses from the villains face.

The helmet appeared in Izuku's hand, he wasn't confident his plan would work, but the power he had granted Fetch worked perfectly: the ability to teleport its Amok to its creator. He watched the fight through Photon's eyes, it seemed removing the Amok from her position hadn't broken the telepathic connection.

The heroes had managed to regain ground, and Fetch had hung onto the horse Miraculous. Now was Izuku's chance: "Fetch, return to me, bring me the Miraculous." The Senti-monster turned around, smashing through a window and dashing into down the street.

Nezu remotely opened his door as Izuku appeared on the camera outside, the teen entering when it did. "I wasn't expecting you back so soon Midoriya. Is this perhaps related to the two heroes who were aided by a mysterious creature." The principal spoke, gesturing to the marble dog that followed the boy.

"I-I'm s-sorry sir, I just thought I could help and-"

"And you did Midoriya, without putting yourself in danger. Not only that, but you've secured an incredibly important object." Nezu gestured to the teen's pocket, from which Izuku pulled a pair of glasses. "Though I must ask, why have you kept your Senti-monster around."

"Well..." Izuku glanced down at the dog, his expression conflicted. "It just seems so real, so... alive. It's just kind of hard to kill it."

"I see. The way I see it, as long as you respect the creatures you create, then there is nothing wrong with you using that power. Though, I would suggest avoiding creating humanoid Senti-monsters, they tend to become fully aware, to the point of being fully human."

"Thank you for the advice, sir." Izuku bent down, scratched the underside of the dog's jaw, then raised his hand: "Fetch, I release you from existence." The teen was too busy staring at the fading purple matter to see the conflicted expression of Nezu's face, and the way he stared at his paw.

Author's notes:

Izuku's vigilante name (not his hero name cause he can't really re-use it now) is the French word for useless, in reference to his original hero name.