Chapter Text
Izuku had made a choice.
Watching him, his mentor, who the young man considered his father figure, lay on his bed, coughing up blood, while his once shining blonde locks faded into a shade of gray.
He still should have time. He wanted Yagi-san to live a long life, and not pass away at the age of forty-eight.
He shifted his gaze to his mother who tried to hold her sobs, looking absolutely wrecked as she was witnessing her second husband on the edge of death.
He was not sure she even noticed he was in the room, her head must have been filled with memories, and feelings she won’t be able to express to his new love.
Izuku’s heart clenched with sorrowful anger. Anger, because he was not doing a thing but standing here, letting everything happen.
Not anymore.
He wasn't the same person he had been. He was not a helpless child.
This time he was going to help.
Even if it meant sacrificing something. Everything.
“Sir Yagi...” He whispered and her mother whipped her head towards him, round green orbs filled with tears much like his very own.
He crouched down and placed his palm on top of his mentor’s. “I- I promise, I won’t let it happen. You and mom... deserve to live together for a very long time still.” He made his promise, trying not to trip on his own words.
“Izuku...” Her mother whispered.
Knowing he has no time to waste, the boy pressed a kiss onto his mother’s forehead and turned back from the door attempting a smile. “Have faith in me, mother.”
And with that, he left the small cottage house and headed towards the forest.
He had no other choice...
...But to summon a demon.
A Demon, but not any kind. He needs one of the most powerful beings from the underworld. He knows it will come with a bigger price since his request is also difficult. It requires a lot of magic, a lot more than any human could produce. Even if he’d transport all of his magic to his mentor, it would most likely fail, killing him too in the process. He didn’t need unnecessary sacrifices. Not when he knew a process, that would most likely succeed.
With a heavy sigh, he placed his grimoire onto the grass in front of him as he glanced at the salt circle, which was supported by his magic. He had gone through the ritual several times in his head, all he needed now was the spell, and his blood.
“I, caro et sanguis, qui nati sunt in hoc mundo ...”
He closed his eyes in contraction, and in his right fist, he clenched down on the knife he’d bought along with himself.
“clamabo potentissimum esse qui inter profundum inferni”
Izuku has been told that it would be easier if he’d say the name of the creature, however, he’s been also told if the demon was currently making another deal with another mortal the summoning wouldn’t work, and the ingredients would go to waste. Izuku couldn't let that happen. So instead, as a loophole, he referred to it as ‘the most powerful’. Midoriya figured it would send him a demon, who is free of any contract and powerful enough to help him.
“animari, ac tenebras, Im 'non est a paciscor abicere eam”
He finished the spell, quickly opened his eyes, and cut his palm, his warm blood flowing down to the salt circle, and from a single drop, it was painted dark crimson. Unbearable heat started forming inside the circle, Izuku made sure he stepped further away. The grass and even the air started burning, red, orange yellow, and blue flames dancing, engulfing the circle in whole.
Even a few feets away Izuku started sweating but couldn’t help the faint smile that graced on his lips. It worked!
“Who are you to summon me, filthy human?”
A rough voice cut through the forest's soft atmosphere, and suddenly Izuku wasn’t so enlightened anymore.
He was definitely not expecting him of all people.
In disbelief, he stepped forward and rubbed his eyes.
But his ears haven’t fooled him.
“Kacchan?”
Crimson angry gaze found his, and if it was possible it got filled with more— rage.
“What the fuck?! Is that you shitty Deku?!” Now, if he had doubted it before, he was sure the creature in front of him was ‘Kacchan’ his childhood friend.
At the age of four, he wasn’t aware that his best friend wasn’t a human. Even if he recalls he can’t remember an outstanding thing that his friend did that would cause people to assume he was a demon. If we don’t count his temper, and violent tendecies of course, but Izuku guessed that’s just how Kacchan was.
So why was he here now, standing inside the circle where his demon was supposed to be?
“Answer me fool! Why did you bring me back to this filthy place? I’ve had enough of it as a brat.” The demon— Kacchan complained further.
Izuku snapped out of his daze as he answered. “Are you really a demon? But how, when—“ with a question.
“Are you blind or something?” Katsuki asked back, flashing his sharp teeth in answer. Now that Deku took a closer look, he could pinpoint the horns that curled up between the ash blonde spikes, and Katsuki’s eyes were still the same bloody red he had remembered, but his pupils weren’t anything human-like as it slit his eyes half. “I’m the demon of wrath, better remember it fucking nerd,” he grumbled. “Now answer. Why did you summon me?”
Izuku’s gaze fluttered back to his face. “I- I want to make a contract!” He exclaimed before he could change his mind.
Katsuki’s eyes now glinted with interest as he smirked down at the greenette. “Oh?”
Izuku nodded as he continued. “I want you to heal my mentor. He’s been suffering for five years since he was seriously injured in one of his last battles.”
“Tch. Human’s just as weak as I remembered.” The demon sneered and crouched down to Deku’s eye level. The green head was sure if he’d stand closer the heat emitting from Katsuki would burn him. “Why can’t your little magic heal him huh? Still too weak on your own Deku?” The nickname came out harsh as it could, Bakugou’s tone dripping with menace.
Izuku furrowed his brows at the patronizing tone but shrugged. This time he didn’t have the upper hand. He wondered if he ever had it actually. “Are you willing to make a contract or not?” He was surprised his voice didn’t shake, despite the situation. If Katsuki refuses then he’d have to find another dose of ingredients which he didn’t have the time to do so.
The hellspawn showed a surprised face even if for a second but Izuku caught it. He narrowed his eyes. “It depends, useless little Deku... What are you willing to offer?” The red irises bore into him, for a silent answer.
“A-anything.” This time his voice was weak but the demon could hear it because an ominous grin spread across his face upon his words.
“Any-thing he says. Aren’t you being a little... imprudent there Deku? “ Kacchan chirped back, while walking closer slowly to the circle's edge. “Not that I care. Once that pact is made, there’s no backing up, you got that?” He warned.
“Yes, I’m sure.”
“Then what are ya waiting for? Chant the spell you useless mage.”
Izuku ignored the insult as he grabbed his spell book from the dirt, flipping it to the right page. “Got it!”
“et malum ex inferno, in virtute Dei...”
Katsuki extended his arm, but couldn’t reach through the magic boundary.
“Dabo Bakugou Katsuki vult aliquid, quod tam diu suum promissum effecerat.” The smaller boy finished the spell, and at the same time blood escaped Bakugou’s hand, and with a quick move Izuku grabbed it and traced his plush tongue on the warm crimson liquid. The spicy yet sweet taste lingered in his mouth as he pulled away slowly.
Midoriya couldn’t help but blush at the demon’s intense stare, he couldn’t place it anywhere. It filled his stomach with an unknown hotness as well, so when he was sure the ritual was successful he jumped a few feet away.
Katsuki, now able to step out of the circle, stretched out one arm as if to test the waters. As soon as he recognized the spell no longer bound him to the circle nor his abilities, a lonesome tree next to them was immediately consumed by raw hellfire.
“Kacchan!” Izuku gasped, not expecting the other's sudden outburst. “What were you thinking, now they’ll assume me with vanda—“
The boy was cut off by a prominent figure pinning him to another tree that wasn’t burned down to its cores. Kacchan’s touch was burning even behind clothes. Izuku let out a whimper of surprise and pain.
“Let’s get over with this shit Deku, so we can focus on my part of the deal.” The blonde hissed out, his breath tickling the smaller boy’s ear. After the demon was sure the demand reached Deku’s brain, he stepped away and crossed his arms.
“Okay uh- yeah! I’ll lead the way.”
Katsuki grumbled but followed after the human nonetheless. If he really had to do this, he better make use of it.
“There, I think mother went for another dose of herbals and medicine not that they’d... help she just... still has hopeI guess..” Izuku walked into the cottage house, letting the demon in who head-butted the small entrance’s upper part.
“What the fuck? How do humans even fit in this tiny fucking place?” Katsuki huffed out a few cusses, rubbing his forehead, as he made his way toward the bed.
“Well, humans aren’t 6’3 most of the time Kacchan.”
The blonde just shot him a glare before turning back to Toshinori, who seemed to be asleep.
Bakugou placed his claws on the older man's stomach, and a blackish-purple aura engulfed the place the demon has touched.
The greenhead watched silently, as his former childhood friend worked, or assumed he was working by feeling up his mentor with his weird but powerful magic. Yes, his magic was indeed striking, so much that Izuku felt a pull towards it. He kept himself together though and kept observing the two figures.
Within a few minutes, Toshinori’s pale face looked more— lively. And even his gray hairs were back in their original shiny blonde color. On his stomach, there was still a scar but it looked so much better than before. It wasn't purple, green, or blue, it was just a normal scar. A huge but normal one.
“There, he should be fine. He may need a day or two to gain consciousness, but he won’t kick the bucket.” The demon of wrath murmured as he retreated his hands from Toshinori.
Izuku gaped with wide eyes, as he touched his mentor’s scar with a careful move. Is he really going to be okay? A few minutes of demon witchcraft and that’s it? Not even the most famous doctors and, shamans could make progress, and now Kacchan—
“Oi, quit the mumbling idiot. I told you he’s healed, didn’t I? I kept my part of the contract. It’s your turn nerd.”
The taller creature pierced his gaze onto Izuku who gulped and nodded unsurely. “ You haven’t exactly pointed out, what would you like in... exchange?”
The demon true to his nature flashed a really wicked smirk. “I want you to be mine.”