Gray continued training and getting used to fighting multiple people at once. He had been sparring against both Frieza and his brother, Cooler, at the same time.
Mirko took a small break from her own grueling schedule and decided to check on Gray. The moment she arrived near his isolated training sector, she stopped dead in her tracks. She could not even see him fighting. She could hear the deafening, earth-shaking shockwaves from the impacts, but her eyes were entirely unable to track the movement.
All Might was also standing at a safe distance, just quietly observing. Every once in a while, the three fighters would briefly appear in mid-air clashing, before blurring out of existence again.
"This is insane..." Mirko whispered, her eyes wide as she stared at the empty, booming sky. "He wasn't kidding when he said he was holding back a lot during our fight..."
She clearly saw just how completely outclassed they all were. Finding a wave of new motivation, she turned on her heel and made her way straight back to her zone. She was already taking her training seriously, but she was now ready to amp it up even more.
As the days passed by, even Aizawa noticed the immense, world-changing potential of this pocket world. If Gray continued opening this dimension so the faculty and the students could get elite advice just like Midoriya was, he had incredibly high hopes for the future heroes. The only thing that weighed on his logical mind as a potential downside was the aging factor. If the students spent too much time in here, they would age faster than the rest of the world.
One evening while they were all having dinner together, Aizawa decided to ask Gray about it directly.
"I wanted to ask," Aizawa began, setting down his chopsticks. "A month passes inside this dimension, but only twenty-four hours pass in the real world. Does that mean that if we bring the students in here, they would age around four years if they used it for a year straight?"
Gray stopped eating, his fork hovering mid-air. He started calculating all the times he had used his Training Dimension since he had gotten it. So far, his own physical age hadn't changed at all. If the internal time actually counted toward their biological cells, he would have been close to 25 years old by now instead of staying a flat 23.
Coming to this conclusion, Gray looked across the table at the underground hero. "I've used this place dozens of times, and so far, I haven't aged a day past my normal timeline. The system locks your biological clock. When you leave, your body only ages a single day per cycle, so there is no need to worry about the kids."
"I see," Aizawa nodded, visibly relieved as he continued eating.
Thankfully, Mirko actually knew how to cook. She had willingly taken over the kitchen duties and prepared delicious, high-protein meals for all of them every single day. Aizawa secretly feared that they would have been forced to eat bland food for 30 straight days, since Gray, All Might, Izuku, and he didn't have a single clue on how to cook properly.
Izuku had been improving by leaps and bounds. He had already upped his Full Cowl limit to 5% and could actually maintain the form for a few hours a day. His stamina drained more quickly when it was active, but he was incredibly glad he didn't have to break any more bones to actually have a fighting chance. Thanks to all the nutritious food Mirko cooked and the non-stop training, his body was getting more and more used to holding the raw power of One For All.
Gray continued checking on the other three when he had the time. Whenever he saw Izuku blitz through Master Roshi's obstacle courses, he would up the kid's weighted clothes a bit more. Surprisingly, Izuku stopped complaining entirely once he saw the visible results. The kid hadn't even started his first official day of high school yet, and he was already significantly stronger and faster than his original canon self.
Aizawa was also making steady progress under Bang, absorbing the defensive parrying forms to elevate his close-quarters combat. Mirko, fueled by seeing the massive gap between herself and Gray, was moving like a blur.
As the final days of the 30-day training cycle began to wrap up, Gray turned his thoughts back to his primary objective. He hoped that once they stepped out of the dimension, Principal Nezu would already have all the information available from Sir Nighteye. Gray's training had successfully expanded his own stamina, and he was completely ready to go get Eri.
The final minutes inside the dimension ticked away, and the void fractured. Everyone was instantly ejected and materialized right back into the real world, landing smoothly on the floor of the UA training facility.
Up in his office, Principal Nezu watched the live security feed and stopped his digital stopwatch. 'Twenty-four hours on the dot,' he thought, a satisfied look on his face.
Mirko was the first one to stretch and say her goodbyes. She still had to handle her duties as a top pro hero, and her own patrol routes were quite far from the school grounds. However, after that month of intense training, she had a few ambitious plans in mind that were bound to give the Hero Commission a massive headache later.
Aizawa was the second one to turn around and head for the exit. He adjusted his scarf and muttered that he needed to catch up on whatever incidents had occurred over the last 24 hours, while also filing his own official report on the training dimension.
All Might bulked up into his muscle form and scooped up Izuku to take him home, but before they could leap away, Gray called out to them.
"Wait up, All Might," Gray said, walking over. He used his clothes beam to manifest a heavy stack of clothes. "Here, take these, Izuku. I made seven more changes of weighted clothes for you to wear daily. Don't go slacking on your training now."
Izuku stumbled slightly under the sudden weight as he took the heavy clothing, but he smiled brightly and said a sincere thank you. With that, All Might leaped out of the facility, leaving Gray all alone in the quiet gym.
With nothing else to do for the moment, Gray walked back to his designated staff quarters and took a quick, hot shower to wash off the dust of the training void. Once he was out, he used his clothes beam to snap on a fresh, pristine set of clothes. Ready for business, he stepped out of the apartment and walked straight over to the administration building to get all the Yakuza info he needed from Nezu.
Gray noticed the door to Nezu's office was open, so he peeked inside. He saw Aizawa handing the principal a fresh folder.
Nezu looked up, spotted him, and smiled. "Ah, just the person I wanted to see! I got these from Sir Nighteye's office, and I was just about to go deliver them to your room."
Nezu stood up on his chair, grabbed a thin file from his desk drawer, and extended it toward Gray. "This is all the info Nighteye has so far. It ain't much since they just started investigating them, but at least it's something to start with."
Gray took the folder, opened it, and started reading right there. The documents contained basic information about a few lower-level Yakuza grunts and some known front companies, but there was almost nothing regarding Overhaul or the higher-ups of the organization.
'This is way less than what I hoped for...' Gray thought, feeling a bit disappointed by the lack of more information.
"Thanks. I'll finish reading it in my room," Gray said, closing the folder.
Before he could step out of the room, he heard a deliberate cough from Nezu. Turning around, he saw the principal pointing a small white paw down toward his own ankle. Looking down, Gray realized he had completely forgotten to put his ankle monitor back on after stepping out of the training dimension. He casually reached into his system inventory, pulled out the electronic tracker, and snapped it right back onto his leg.
After Gray left the office, Aizawa continued explaining to the principal exactly what he had experienced inside the pocket world. He detailed how Midoriya and Mirko had been assigned their own trainers, and how the different training routines were perfectly suited to help them both grow.
"All in all, it's a great ability that could heavily help us out in the future," Aizawa finished, wrapping up his official report. Nezu nodded slowly, his mind already spinning with ways to integrate the weird young man's power into UA's curriculum.
Gray back in his room continued reading the files over and over, memorizing every face, name, and neighborhood the Yakuza grunts frequented. By the time the clock on his nightstand hit 3:00 AM, he opened his system interface to buy the next upgrade tier.
[New Upgrade]
(300 Gold) 30 Gold/Hour ✔
[New Hourly Rate]
69 (63) Gold/Hour
Gold: 25
'69 gold per hour... nice,' Gray thought with a smirk. He closed the folder, tossed it onto the nightstand, and lay back on the bed. Slowly but surely, his eyes started closing until he fell asleep.
The next morning, Gray sat up and checked the time. It was 9:00 AM. Opening his status info, he saw that he only needed one more hour of passive generation to afford the next upgrade. Curious about his long-term plan, Gray opened the system shop to double-check the tracking item he wanted. Sitting there at exactly 10,000 Gold was the {Magical Compass}, a one-time-use tool that could point him in the physical direction of anyone he chose, including Eri. Seeing how quickly his hourly rates were climbing, he knew he would be able to afford it soon enough without relying on Sir Nighteye's slow investigative work.
Closing the shop interface, Gray washed his face, brushed his teeth, and walked out of his room. He still had plenty of time, so he decided to head out into the fresh morning air to explore the rest of the massive UA High campus.
After exploring for a bit longer, he came across some of the training "cities" that were built inside the school grounds. He walked through the empty streets and explored the vacant buildings, checking out the urban layouts.
While he was at it, he noticed that the hour had passed. He immediately opened his interface and bought the next upgrade tier.
[New Upgrade]
(500 Gold) 60 Gold/Hour ✔
[New Hourly Rate]
135 (123) Gold/Hour
Gold: 8
Closing the interface, Gray continued exploring the area. Up in the main tower, Nezu kept following his every step through all the security cameras scattered around the training grounds, keeping a close eye on his new guest. Gray really wanted to fly out of the campus right now and start actively scouting the neighborhoods the Shie Hassaikai grunts visited all the time. However, he knew that if he just broke containment and took off into the city, he would cause a massive political headache for Nezu with the Hero Commission.
Gray, after exploring around for a few more hours, decided to head back to the teacher's housing block. On the way, he stopped by the main office and asked Nezu if he had a computer he could lend him. Nezu happily obliged, providing him with a state-of-the-art laptop for personal use. Gray thanked him, carried the machine back to his room, and set it up on the kitchen counter.
In there, he started browsing the internet for anything useful, looking up local news, forums, and hero databases. He already knew about all the devastating future events, the League of Villains, All For One, Re-Destro, the catastrophic Paranormal Liberation War, and the massive Tartarus prison break. Thousands of innocent people were destined to lose their lives in this world just because the so-called "Heroes" were too afraid to use lethal force and put murderers and monsters down for good.
But Gray wasn't bound by their rigid, naive rules. What he knew for sure was that once he found Overhaul, he wouldn't hesitate for a single second to put the bastard down permanently. Whoever was perfectly fine with tearing apart and torturing a little girl day after day, no matter how demented their logic was, deserved no mercy. Gray was willing to become the number one enemy of the hero society if it meant he could put those monsters deep into the dirt.