Izuku Midoriya didn't know who the orange-haired man with the sword was. To find him standing over a civilian he wasn't there to save in time, and then to dodge Blackwhip and draw his blade in front of the hostages, had given him the impression the man was a partner to the criminals. But Danger Sense didn't tick at the sight of him, and the civilians didn't cower away from him, so maybe he was a new hero or sidekick Izuku didn't know about — which was odd, because he knew about eighty percent of Japan's hero force by their looks. He was the country's eighth highest ranked hero now; it was beneficial to know friend from foe.
When the screams of Danger Sense in his ear pointed him towards Tartarus, he knew foe.
Izuku looked over his shoulder to the orange-haired swordsman flying by his side, heading towards the approaching prison in the distance. "Could you feel that too?" he asked the other man. He hadn't met many others with quirks like his Danger Sense or the late Sir Nighteye's Foresight.
The man flickered his gaze to Izuku for only a moment before looking ahead again. "Do you know anyone strong who can fight blind?"
The green-haired man blinked at the sudden question diverting from his own. "Uh, no?"
His answer brought a troubled sigh from the orange-haired man's lips. "Look, I'll handle this. Just get any living soul out of the area as fast as you can; they seem to like you a lot." Before Izuku could unpack that stack of words, the stranger sped up, flashing in and out of existence before his eyes like a shutter camera.
The green-haired hero cursed under his breath, blasting himself faster through the air with a bump to One For All and an Air Force blast to propel him. He reached Tartarus in no time, but the strange swordsman was nowhere in sight. The guards at the front entrance were hesitant to approve his own entry into the facility — worryingly not knowing of the orange-haired stranger that was ahead of him — but relented when one warden was informed of his arrival; whoever was triggering his Danger Sense was obvious enough to warrant his help.
Running alongside the guard who led him down through the bowels of the prison, Izuku kept and eye for the strange swordsman. For someone who spoke Japanese so fluently and presented themselves in uniform so uniquely, the green-haired man hadn't recognized an inch of him. He wasn't fluent in swordsmanship but with the dangers of using such a weapon for hero work so pronounced, someone using a blade of their own height should have caused a stir for him to notice. Especially if they had such speed and flight in their quirk he was pretty sure it put Hawks to shame with how easy the man made it look.
Once they finally reached their floor — one he knew all too well belonged to the man who almost vaporized Japan — a warden made himself known to intercept him. "We've been sending out warnings to every station we can reach," the gruff bloodhound man informed him, leading them down the hall. "We haven't even sent one out to anyone in the top ten. You could tell what happened?"
Izuku gave the other man a weak smile. "'I'll know danger from a county away' isn't just a promotional slogan," he clarified without naming his utility quirk. "It's like my head is screaming at me to turn tail and run. What happened?"
"Shigaraki is gone." The straightforward answer nearly tripped Izuku over his own two feet, but the frustrated warden and his troubled guard didn't bat an eye. "A new man is in his cell, already bound to a chair with a binding we don't recognize. He wasn't teleported or escaped; security footage shows him there one second, and in the next he's completely replaced. Sensors don't locate him anywhere across Japan. We're sending encrypted reports to every police station and hero agency we can without alerting the press. Let's hope your sudden stint doesn't tip them off."
The green-haired hero mulled over his frown, hastening to take the lead towards the cell. "Tenko's mentally unstable; whoever moved him is either trying to reactivate his quirk or has already been killed by it. The teleportation quirks we know of can't reach too far. Send a message to the Koreas and Russias of anyone near their ports that shouldn't be, on the off-chance. What do we know about our new convict…"
It took looking beside him for Izuku to notice the warden and the guard had stopped along the way.
"We can't get anyone close to him," the warden panted, dabbing beads of sweat from his forehead. The younger guard beside him stumbled backwards, tugging at his own collar as though it was suddenly too tight. "We don't know who he is or where he came from, nor the men or women he's named. We tried sending a unit into the cell; the first man that stepped in evaporated on the spot; whoever bound him didn't restrict whatever quirk that is of his. You don't feel it?"
No he did not, Izuku admitted wordlessly. Beyond Danger Sense still ringing distantly in his ears, he couldn't feel a thing in the air, not anywhere to the level these men could. Did this new threat really have an aura of a quirk dangerous to organic material?
The warden took his silence as his answer. "The room is yours." He stepped back to follow his guard, saluting the green-haired man. "We'll be watching the live feed and provide any mechanical assistance we can, in case he acts up. Thank you for troubling us."
Izuku nodded to the man before turning to the door before him. There would still be a glass wall between him and the man in Tenko's place, but there was no ease off the pedals. This new man screamed danger in his existence alone, sitting in containment yet oozing endless threats. Not even All For One triggered his quirk like this. Just who was he?
The first sight greeting him upon entering the room was the back of the orange-haired man's head — his giant, wrapped sword holstered on his back — standing in the confined room with their new convict.
It wasn't a long wait in his new cell before Sosuke Aizen found himself amidst new company phasing through the roof. The spiritual pressure was unmistakable on its journey over, but he found interest in seeing the new maturity of the experiment he crafted so long ago.
"Welcome, Kurosaki Ichigo," he greeted the orange-haired man, much to the Substitute Soul Reaper's sneer. "I take it you are not the guide to my newest confinement? I don't believe we've been apart long enough for you to die and Central to appoint you to such a lowly position."
Kurosaki took a look around the pristine white room — the gun-armed cameras in the upper corners, the large glass wall splitting the room in half, the nearly invisible door in the back corner — and whistled. "This place looks like it costs more than my car," he commented. "I doubt Mayuri would spend even half of that on a new room for you."
"How is Kurotsuchi these days?" the bound soul prodded.
"Batshit insane," the orange-haired man answered without missing a beat.
Sosuke bowed his head with a smile. "True to his character, as always." When the living soul didn't respond with another comment, he upturned his head and asked, "What is it you want?"
Kurosaki turned on him, a sour mood tearing away any trace of a smirk. "What makes you think I want anything from you?"
"Toys always turn to their creators for answers," the brunette answered, humming delightfully at his experiment's grunt. "Given the lack of reishi in the air and the pitiful distribution of spiritual energy with it, I can only assume we're in the mortal world. Japan, if these voices attempting to threaten me are anything to go by, and the gnats they tried to send in to interrogate me." He glimpsed to the corner of the room, and the voice box dangling under the gun pointed at his head. "I didn't expect to return to your soil anytime soon, so I only suspect you're here for answers regarding my presence."
The human soul examined him, contemplating his next choices of action, before crossing his arms and snorting. "Got it in one."
"Then believe me when I tell you I haven't the faintest idea. I grew familiar with the darkness for so long; this bright light managed to take me by surprise. There was no warning, no message passed along, no one to tell me of what was to come; suddenly, I was moved here. Against my better health, to no one's surprise." His eyes followed along the trails of his wrappings, stretching across the floor and disappearing at the edges where it met the walls, leaving the locks to his bindings out of sight. "An act of relocation clearly made by someone in power, no doubt about that."
Sosuke eyed past the Substitute Soul Reaper, following the encroaching spiritual pressure behind him. A condensed figure of high power, but not one the fused being recognized. Nowhere near the level to prove themselves as a threat to him. But to be present in the mortal world ruled out the Gotei and the Arrancar, so maybe it was some lingering Quincy or a new Fullbringer under the orange-haired man's wing; the latter would prove to be a great annoyance with the right skill, why else would Kurosaki bring them so close to his presence?
"For a snake who had his ear to the wall in everything, that surprises me," Kurosaki summarized his response. "Even trapped in the Muken before, Shunsui said you knew too much. Though it isn't like I can take your word at face value."
"I see the new head captain has indoctrinated you into his drinking circle. Believe my word or not, I do not have all the answers to the universe. And with these restraints, no means of abusing what knowledge I do have. Will Kiskue be joining us soon? I can't imagine you're the only one who wishes to see me."
Sosuke would admit nothing out loud, to his own confusion regarding the orange-haired man's troubled expression of a response. That damned scientist had made it out of the Quincy Invasion alive, he knew that much, and with the last remaining power of all the realms quelled there wasn't much that could hope to put him down for good. He eyed the approaching power behind Kurosaki once more, as it broke off from the beings it dwarfed and made its way ever so closer to them.
"Or has our mutual friend sent you here to kill me?" he egged on, looking into the other man's hazel eyes. "I imagine it can't be easy, for a boy who tried so hard to save souls and could never deliver the killing blow until reality itself was at stake. I assume that's why he delivered you to me with" — the door behind the Substitute Soul Reaper whirled open, and from it stepped out a green-haired man in a tracksuit — "back-up."
Kurosaki looked back over his shoulder to the other young man, who in turn looked between both men in the cell with bewilderment and shock, and Sosuke took his time analyzing the new arrival. Definitely not a Soul Reaper or Kido Corp agent, given the lively flesh that covered his body; he was almost inclined to determine Fullbringer if it weren't for the swelling power within. That wasn't the remnant of a Hollow, those were multiple souls overlapping each other in a faux appearance as one; and Souske knew of one creation like that.
"I doubt our friend here is an official member of Squad Zero," he theorized aloud, gazing at Kurosaki cheekily. "And I would think Kiskue too reserved to create the Oken himself with such a pitiful gathering of souls. Head Captain wouldn't allow the birth of such an abomination from such an esteemed friend. What is your name?"
The green-haired man furrowed his brows at Sosuke, but turned his attention to Kurosaki instead. "You can't be in there," he quickly reprimanded the Soul Reaper.
The orange-haired man rose a hand his way. "Sorry, but let me deal with him. I can handle this."
"Quite bold of you, Kurosaki," Sosuke noted, "to think yourself still capable. Even bound, you can't kill me. Soul Society would punish you for even attempting to carry out what they are too afraid to attempt."
"Big talk coming from a mummy," Kurosaki bit back.
The green-haired man all but slammed on a button against the wall and faced the speaker above it. "Why didn't you tell me you let him in? What about the guard he killed?" Kurosaki's frown deepened once his ears picked that up.
"You killed someone?"
"They got too close," Sosuke reasoned. "I told you they sent someone to interrogate me. I couldn't even see the mortal before he was erased. These walls have held up much better than him."
"There's no one else in the room but him," a voice explained over the intercom. "He's been talking to himself for the past few minutes."
"Have you told him nothing?" Sosuke asked Kurosaki. "Who I am, or why only he sees a Shinigami? Does he even know what he is, what he carries or the purpose of it? Did someone try recreating you? I never thought you would be so heartless as to leave a fellow experiment in the dark."
Kurosaki growled. "For once, it's funny seeing you in the dark about everything. Makes you deservingly small."
"I would watch your growing hubris, Kurosaki," he warned coyly. "Last I remember, Yhwach took the powers your mother and I gave you."
The blade was against his throat in a second. Kurosaki held his blade in one hand, barely moving where he stood other than to press his zanpakuto against Sosuke's neck. "Just because I lost the powers of White and my mom doesn't mean I got any weaker. You know that. And the Hogyoku knows that, too." Sosuke dropped his smile at the mention of the item merged in his chest. "You know you're not strong enough to beat me. And I'm not letting you leave this chair."
The young man's show of confidence was one sight on its own, but more interesting was the man on the other side of the glass, glowing as green electricity danced around his body. "Put down the sword, Kurosaki," he warned the Substitute Soul Reaper. Spiritual pressure rolled off him like a tsunami, but neither men in the cell budged an inch by it. "He's not leaving that cell regardless. He'll face punishment for what he's done with his quirk, but don't kill him."
Sosuke looked at his reflection in Kurosaki's blade as the other man contemplated his next action. For a measly amount of human souls such power shouldn't be present in a personified Oken, and no Court Guard without Yamamoto would allow Kurotsuchi to modify high-ranking Soul Reapers into any human. And even in a world so thin of spiritual pressure, there should have been clumps where Kurosaki's allies would be found, the mad scientist and his cat included. And 'quirks?'
Sosuke upturned another smile to the man he aided in creating. "If you are to believe anything I say, then believe I do not forget a second of our fight. There has not been a day yet that I do not reflect upon it. Trust it is still fresh in my memory."
Their stare down lasted only a few seconds before Kurosaki withdrew his zanpakuto, holstering it to his back once more, and wordlessly turning away. He phased through the glass wall with ease, much to the green-haired man's surprise, and directed his way to the door the other man came through.
"Before you leave," he stopped the two young men, "allow me to leave you with one more question for us all to reflect upon." Almost begrudgingly did Kurosaki turn around with the green-haired man to follow. "Of all the worlds in the multiverse, why did Yhwach send us to this one?"