—I don't think this is a good idea— Tokoyami said, hesitant and worried.
—What is not a good idea, Tokoyami, is to ignore the danger you pose to everyone around you— Tetsumaru replied with his flat tone, his words hitting the boy hard and making him take a step back.
But the shinobi continued talking, indifferent to Tokoyami's reaction.
—Imagine if, for example, you find yourself needing to participate in a night operation and a battle against villains breaks out. Don't you think your inability to tame Dark Shadow would put the lives of your comrades at risk? Or would you abandon any call of duty if there is no sunlight for you to feel at ease?— Tetsumaru expressed.
Beside him, Aizawa didn't know whether to nod at his student's point or shake his head at the lack of tact.
Tokoyami fell into deep reflection. He wasn't so foolish as to have never imagined such a scenario. He just didn't expect the moment to come so abruptly.
—It's still daytime. We will only keep you there until I consider it dangerous. Tetsumaru can protect you, and if things get out of control, he will simply remove the sand, and I will suppress Dark Shadow— Aizawa reassured his student.
The Hero and Teacher had to admit he was interested in this special training proposed by Mei the previous night. It would be very difficult for him to find a safe method to push Tokoyami during the day.
The boy looked at his classmate and then at Aizawa, sighing in defeat and placing his trust. He considered that Tetsumaru could contain Dark Shadow, and even if something went wrong, with the sun in the middle of the clear sky and his Sensei there, it would be difficult for him to hurt anyone.
Besides, this was a great opportunity to face Dark Shadow at its full power and with minimal risks.
—All right, Sensei, Tetsumaru. I am ready to face the darkness within me— Tokoyami spoke with determination in his eyes.
The trio moved slightly away from the training area, as Tetsumaru couldn't confine Tokoyami to a very narrow space unless he wanted his Quirk to hurt him.
After a while, Tetsumaru stopped them and drew a large amount of Satetsu from his seals. Aizawa, looking seemingly sleepy, couldn't help but glance at the extraction process, remembering the PussyCat's words.
Now more than ever, he was curious about the dark-haired boy's Quirk. One that was thought to be an emitter type of sand, but now seemed like an energy emitter. In either case, the problem remained the same: He couldn't nullify it.
He quickly dismissed those thoughts. He couldn't continue like this if he intended to mend the trust with his students.
For his part, Tokoyami waited in anticipation for the training to begin. However, a flash of worry shone in his eyes when he realized the proximity of Tetsumaru and Aizawa.
—Sensei? Wouldn't it be better if the two of you stayed out of my reach?— he asked the hero.
Aizawa didn't answer, turning to Tetsumaru instead. Tokoyami's gaze then shifted to the shinobi, who shrugged casually.
—We'll be fine. Besides, it would be quite cruel to get you into this mess and leave you alone.
—But...—
—Don't worry. In terms of containment, Tetsumaru is the best in the class, and I'm not someone easily knocked down— Aizawa interrupted, placing a hand on the boy's shoulder.
—Trust your classmates and your Sensei— the man said with a slight smile, pretending not to notice the tremor in Tetsumaru's eyelid.
—I only have one thing to argue— the shinobi began, staring fixedly at Tokoyami. —Don't treat Dark Shadow as your enemy. He is part of you, he is you, and you are him.
With that declaration, Tetsumaru put his hands together and formed the Tiger seal. It wasn't that he normally needed it, but what he planned to do was on a massive scale, and the gesture helped with chakra concentration.
With his will and a good amount of chakra disbursed, the Satetsu extended over forty meters high and nearly twice as wide and long, slowly forming a gigantic box.
More and more of Sunagakure's most powerful weapon came out of the seals, thickening the walls with tons of dense, compressed material.
As the sunlight was obscured, Tokoyami felt the agitation of Dark Shadow within him.
To Tetsumaru's embarrassment, it took him about thirty seconds to form the box and solidify it completely, a persistent tug in his mind bothering him with the effort of keeping such a thing floating in the air.
—Ready?— he asked, trying to sound casual. He could barely contain the faint grunt due to the strain on his head.
He promised himself to train his ability to control enormous amounts of solid sand in the air more seriously. It was not the same as throwing it and attracting it back later.
—Ready— Tokoyami announced.
Tetsumaru dropped the structure over their heads while creating a smaller version for himself and Aizawa, with bars so their voices could reach the boy.
The box hit the ground thunderously, cracking it and sinking a couple of meters into the earth, sending a shockwave that destabilized the unsuspecting Tokoyami.
The dense sand completely blocked the sunlight, plunging the interior into a blanket of absolute darkness.
—Let him out— Aizawa said in a serious tone.
With a low growl, Tokoyami stopped fighting his Quirk, and Dark Shadow lunged with unrestrained fury, or perhaps glee, against the structure that sought to contain him and enabled his existence.
The creature thrashed in the darkness, its size rivaling that of the summons of a certain shinobi trio. Its claws sharply displaced the air, the impacts shaking the surroundings and sending vibrations throughout the Satetsu box.
Tetsumaru gritted his teeth and sent more chakra, forced to reinforce the walls against the monstrous strength of Dark Shadow.
—Don't fight him. Unite your mind with his and reach an agreement!— Aizawa shouted. He didn't know how much stamina the shadow would have, so letting it run wild until it got tired was not a viable option.
He wanted Tokoyami to control Dark Shadow, but forcefully subduing him would only limit him. He needed to coordinate with his Quirk, not fear it or make Dark Shadow fear him.
The sound caught the attention of the boisterous Dark Shadow, whose gaze shifted to the Satetsu cage behind it. Its golden eyes pierced the figures of Tetsumaru and Aizawa, seemingly unaffected by the lack of light in locating its prey.
—B-be careful!— Tokoyami groaned as Dark Shadow lashed out at his classmate and his Sensei.
With his sand invading the entire space, both through the walls and the slight dust in the air, Tetsumaru used his perception through the Magnet Release to sense the shadow's movements.
He mobilized a platform of sand under his feet, holding Aizawa, and quickly retreated from the spot. An instant later, the small cage was smashed to pieces by the giant shadow.
However, the sand that formed it did not disperse into specks of dust. Instead, it joined another large quantity that the shinobi left on the ground and clung to that limb of Dark Shadow, limiting its movements.
Before the shadow could react, a wave of dense sand held its other limbs, chaining it in place and making it roar thunderously, annoyed by the restraints.
The entity shook wildly, straining the sand that held it. The floor cracked, and entire sections lifted, but the Satetsu continued to penetrate deeper into the earth, solidifying in key areas to effectively immobilize Dark Shadow.
—Can you hold him?— Aizawa asked Tetsumaru, using special night-vision goggles to see what was happening in front of him.
He was truly impressed by the ability of the iron sand. Now he understood the boy's confidence in disobeying orders and jumping into battle during the USJ attack.
He was only bothered by the fact that he didn't deploy this type of power during that confrontation.
—It won't be a problem for now— Tetsumaru replied, his hands still forming seals to mold the chakra with greater precision. —Should we start now?
Aizawa looked at Tokoyami, who seemed to be on the verge of losing consciousness and being dominated by his Quirk.
—Yes. Force them to work together— the Hero nodded.
With the signal given, Tetsumaru lifted an immense amount of Satetsu and formed dense, person-sized balls, hurling the rain of projectiles against Dark Shadow.
They couldn't expect Tokoyami to subdue or convince his Quirk to be friends with pure willpower. They needed to create a situation where the shadow needed Tokoyami.
And what better situation than taking a beating?