"The upper level wasn't great, but the underground is surprisingly spacious."
After climbing down the ladder inside the passage, the three of them arrived in a wide, brightly lit corridor.
The surrounding walls were covered with white metal panels, glowing with a pale sheen under the overhead lights.
"Those walls look solid," Todoroki said, knocking lightly on the metal surface.
"Then there's only one way forward," Masata replied calmly.
"Which actually saves us a lot of trouble."
As they moved deeper, several doors appeared along the corridor. However, inside each room were only piles of debris and various incomprehensible medicines. There were no signs of people—let alone the so-called doctor.
"Hey, monkey," Masata said impatiently, glancing back.
"How much farther is this passage?"
The monkey, shrinking at the very end of the group, trembled slightly before replying.
"It's… it's almost there. Just a little farther."
His fur shook as he spoke, scratching his ear nervously, clearly frightened of Masata.
"…Hm?"
Suddenly, a cone of ice burst from Todoroki's side, instantly freezing the monkey in place.
"What are you doing?!" the monkey shouted in panic.
"I've been leading you the whole time! Why are you hurting me?!"
After struggling unsuccessfully, the immobilized monkey yelled in grievance.
"You've been acting strange for a while now," Todoroki said coldly.
"You keep touching your ear. I finally realized why."
He continued calmly, "There's a device implanted there, isn't there? You've been transmitting our position to the doctor this entire time."
"That's why we haven't seen anyone."
The monkey's face drained of color.
Masata immediately understood—they had been deceived all along. Even with his life at risk, the monkey had remained loyal to the doctor.
Exposed, the monkey lowered his head in silence.
BOOM!!
A thunderous crash erupted from the corridor beside them. The white steel wall was smashed apart as a massive rhinoceros burst through.
The enormous beast surveyed its surroundings for a split second—then charged straight at Masata.
It was like a living bulldozer.
Everything in its path was obliterated. Ice shattered underfoot. The frozen monkey was impaled by the rhino's massive horn and sent flying deep into the passage.
"Hey, hey… that hide looks pretty thick," Masata muttered.
The rhino's gray-white skin gleamed with a metallic sheen.
Boom!
A massive iceberg erupted from beneath Todoroki's feet, crashing toward the rhino.
Crack—crack!
But things quickly went in the worst possible direction.
The rhino showed no hesitation, smashing through the ice with brute force and continuing forward without slowing down.
"Looks like ice won't work," Masata said lightly.
"Maybe its skin is antifreeze."
Clenching his fist, Masata rushed forward.
"Then I'll just knock it flying!"
"Volcanic Eruption!"
BOOM!!!
The magma-coated punch slammed directly into the rhino's horn—
—and was completely blocked.
"Tough little brat," the rhino rumbled, shaking its head before stopping.
The fact that it could speak made it obvious—it was another product of the doctor's experiments.
"Tch," Masata clicked his tongue.
Even his overwhelming punch hadn't caused any damage. This creature was clearly on a completely different level from the surface guards.
"Since you punched me," the rhino growled,
"I'll return the favor."
Its massive body twisted violently, shrinking and reshaping until it became a half-human, half-rhinoceros monster.
"Huh?" Masata frowned.
"That transformation looks familiar. I've seen something like this before."
He recalled the tiger-man he had defeated earlier.
"Don't compare me to that unfinished product!" the rhino roared.
"I'm the strongest modified being!"
Enraged, it charged forward again.
"It's faster now," Masata noted.
"Smaller size, higher speed… I wonder if the strength dropped."
Even to Masata, the rhino-man's movements were frighteningly fast—on par with professional Pro Heroes who specialized in physical enhancement.
Todoroki didn't stand idle.
After realizing that ice alone wasn't effective, he switched tactics.
Flames erupted from the left side of his body.
Under his father's watchful presence, Todoroki could now freely use both halves of his power—a major breakthrough.
Blazing fire swept through the corridor, instantly turning the enclosed space into a furnace.
"You're ruthless," a voice complained from within the flames.
"You burned yourself along with me."
A figure emerged from the inferno—it was Masata.
Aside from looking slightly disheveled, he was unharmed. His combat uniform was heat-resistant, after all.
He shot Todoroki a glance, understanding the situation.
"Sorry," Todoroki said.
"I'm still not great at controlling fire."
"It's fine," Masata replied, dusting himself off.
"Your flames are hot enough. That thing should be roasted by now."
Todoroki exhaled slowly, confident that the rhino-man couldn't withstand that temperature.
"Useless."
The cold voice from within the flames shocked them both.
The fire split apart as a figure walked through—it was the rhino-man.
With a single motion, it slammed its hands outward, extinguishing the flames completely.
It stood there unscathed.
But it had changed.
Its once metallic skin had fully transformed into solid steel, with white steam still rising from its body.
"This…!" Masata's pupils narrowed.
Not only could it transform into a rhino—it possessed another quirk entirely.
The realization sent a chill through him.
This is just like a Nomu…
But unlike Nomu, this rhino-man was fully conscious. Intelligent. Self-aware.
That made it far more dangerous.
"Could this doctor…" Masata thought grimly,
"be connected to All For One?"
Staring at the steel-skinned rhino-man preparing to attack again, Masata felt genuine unease for the first time.