Chapter 13: Technique Effects
"Ren—want to go another round?"
On the training field, the brass-and-steel humanoid stomped toward him with heavy clang, clang footsteps. Its metallic jaws opened and closed as a mechanized voice echoed out.
"No," Ren snapped back to himself from his thoughts and smiled apologetically.
"You guys keep training. I'll watch for a bit longer, Mechamaru."
Mechamaru nodded. The bright green bulb-eyes rotated slightly as he studied Ren for a moment, then turned away and clanked back toward the center of the field.
Ren's physical strength was twelve times that of an ordinary human.
For most jujutsu sorcerers, engaging him in close-quarters combat was simply impossible. Only Mechamaru—whose body, as a cursed corpse, was literally forged from metal—could barely manage to spar with him head-on.
Even so, over the past few days, Mechamaru's steel body had accumulated a fair number of scars. Several repairs and component replacements had already been necessary. Even the chest armor plate he'd had replaced just yesterday was now dented and pitted after that morning's bout.
Of course, none of this posed any real problem for Mechamaru.
A cursed corpse felt no pain, and damaged parts could be swapped out at any time. Ren was one of the few opponents he'd ever encountered who could truly push his mechanical frame to its limits. That overwhelming physical power made Ren the perfect test subject for stress-testing his body.
Because of that, Mechamaru genuinely enjoyed sparring with him.
And yet—
Lately, Ren had seemed oddly distracted.
His heart no longer seemed fully in these exchanges. From time to time, his gaze would drift, as though his thoughts were already somewhere far beyond the training field.
Ren sat on the stone steps at the edge of the training field, watching Mechamaru return to the center and resume practice with Miwa Kasumi and Mai.
Compared to the restraint Ren showed when sparring with Mechamaru, the situation was reversed here—this time, it was Mechamaru holding back.
Ren could tell. Mechamaru's movements were careful, deliberately restrained. More than that, every time the exchange ended, the metal-bodied cursed corpse would even praise his opponents' strength, putting on an act as if the fight had been exhausting.
Seeing that lump of metal handle human social niceties so skillfully carried an unexpected sense of comedy.
After watching for a short while, Ren's attention drifted again, his thoughts sinking inward.
"Hey."
At some point, Mai had walked over and stopped in front of him.
"You're still thinking about that fire-type cursed spirit's technique, aren't you?"
Ren nodded.
"I was thinking…" He raised his hand, casually forming a short blade of glowing blue cursed energy. The blade extended and retracted in his palm, morphing smoothly into different shapes.
"This counts as a change in form for cursed energy."
"Then is it possible," he continued, "to make cursed energy undergo a change in nature instead—like turning it into flames?"
"Form change, nature change…" Mai planted her hands on her hips, brows knitting together.
"You sure you're not in the wrong franchise? This is the jujutsu world. The Naruto set is next door."
Ren paused.
"…Fair point."
Mai tilted her head, studying him with growing curiosity.
"By the way, why are you so obsessed with other people's techniques?"
Then her expression softened into something almost sympathetic.
"Is it because your own technique isn't very useful?"
She brightened immediately afterward.
"Actually, we still don't know—what is your innate technique?"
She'd been curious ever since the first day. Ren was already terrifyingly strong without using any technique at all. If he activated one… it was hard to imagine.
A hint of hesitation crossed Ren's face.
The moment Mai saw it, she understood. It was a look every rookie sorcerer wore at some point.
"Worried about leaking your abilities?" she asked casually. "You really don't have to."
"Why not?" Ren looked up, genuinely puzzled.
"Because in a real fight, your enemy is going to learn your technique anyway."
"What?"
"Do you know what a binding vow is?" Mai asked, sitting down beside him.
One glance at his blank expression gave her the answer, so she continued.
"In the jujutsu world, there's a system where you impose restrictions on yourself in exchange for greater power. Pay a price, get a benefit. That's a binding vow."
"Out of all of them, the most common one is technique disclosure."
"By revealing your technique to your opponent, you strengthen its effect."
"…You can do that?" Ren's eyes widened in disbelief.
Judging by her serious expression, she clearly wasn't joking.
Ren's mind instantly conjured a ridiculous image: two enemies standing still before battle, calmly explaining their abilities to each other like it was a strategy meeting.
What is this, an anime?
Still, the explanation eased the faint hesitation he'd been carrying—though, truthfully, he'd already explained his technique's effect before, to Utahime and Nishimiya Momo. Old habits died hard.
He opened his mouth, ready to explain—
Then changed his mind.
Smiling, he looked at Mai and said,
"Hit me."
"…What?"
Mai stared at him, mouth slightly open.
"You're serious?"
"Hit me." Ren stood up, still smiling.
Mai had never heard such a shameless request in her life.
Shameless or not, she certainly wasn't about to indulge him gently.
She sprang to her feet, clenched her fist, and swung straight at his chest.
—And missed. Completely.
Her punch skimmed past Ren's arm, throwing her off balance. The next instant, she crashed straight into him.
Ren reached out and steadied her.
"H-how is that possible…?" Mai's breathing was uneven, her cheeks flushed—whether from the collision or from failing to satisfy such an infuriating request, even she wasn't sure.
"T-that was a mistake! A total mistake!" she snapped, raising her fist again.
This time, she was deadly serious.
She planted her feet, stabilized her center of gravity, calmed her breathing, carefully aimed—and then threw the punch with full intent.
She would not miss.
And yet—
She collided with him again, even harder this time. Their faces came dangerously close, her lips nearly brushing his.
Mai tore herself free, her face burning red.
Impossible.
She admitted she was weaker than him—but missing basic punches? That was absurd. Was she suddenly disabled or something?
Furious, she raised her fist again—
Then stopped.
Seeing the half-smile on Ren's face, realization struck her like lightning.
"…This is it, isn't it?" she asked slowly.
"Your technique."
Ren smiled and nodded.
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