The tip of the kunai touched the granite surface.
Time seemed to stretch in that moment.
Roy focused all his mental energy on maintaining the precarious balance of energy at the tip of his finger.
He could clearly sense the chakra cage emitting an agonized groan, while the Armament Haki inside it was like a provoked beast, frantically ramming against its restraints, desperate to be unleashed.
At the moment of contact, there was no explosion, no sound.
An invisible, unsettling ripple spread from the tip of the kunai.
A ripple like water appeared on the hard surface of the granite. Immediately after, a pitch-black hole, as thick as a thumb and with a cross-section as smooth as a mirror, silently appeared in the rock.
The hole rapidly deepened and penetrated through.
The entire process was eerily quiet.
The stone pointed to by the kunai's tip didn't shatter or turn to powder; it simply vanished.
It was as if its existence, along with all the matter composing it, had been completely erased from the world.
Roy maintained this state for only two seconds.
After two seconds, the chakra circulation within him collapsed with a roar. The Armament Haki, which had lost its driving force, instantly dissipated without a trace.
An overwhelming wave of fatigue swept over him like a tsunami. He stumbled, using his other free hand to brace himself against the ground to keep from collapsing on the spot.
He panted heavily, large beads of sweat rolling down his temples and dripping onto the ground.
On the granite before him, a perfectly circular hole, clean through, with impeccably neat edges, remained.
Through this hole, the wind-swept trees behind it were clearly visible.
Looking at his handiwork, Roy's eyes held no trace of joy, only a deep-seated apprehension rising from the depths of his heart.
This was entirely different from the dent he had previously pressed into the iron ingot using pure Armament Haki.
That dent was merely the application of force on a physical level. This hole, however, was an erasure at a deeper, almost conceptual level.
Thunder Annihilation, the power of annihilation.
The name he had given this power was so precise it sent a chill down his own spine.
After resting for a brief ten minutes or so, waiting for the dizziness to subside slightly, Roy stood up and began more meticulous testing.
He had to act like the most rigorous scholar, understanding every parameter and detail of this trump card he held.
He needed a scale that could accurately measure this power.
He gripped the kunai again. This time, he deliberately reduced the amount of Armament Haki he mobilized, using only about a third of what he had used before.
The consumption of chakra decreased accordingly, and the searing pain lessened significantly, becoming bearable.
He touched the kunai to another spot on the rock.
Again, silent annihilation.
A smaller hole appeared in the rock, only as thick as a little finger, and its depth stopped at about halfway through the rock.
He understood immediately.
The destructive power of Thunder Annihilation was directly proportional to the total amount of Armament Haki he invested.
And chakra was the container that determined how much Armament Haki he could hold.
His current total amount of chakra was his biggest weakness at the moment.
Next was a test of duration.
He concentrated a medium-strength Thunder Annihilation. This time, instead of unleashing it, he tried to maintain the state of energy adhering to the kunai.
One second.
Two seconds.
He felt the kunai in his hand begin to vibrate slightly. A sense of foreboding rose within him.
Three seconds.
The kunai's vibration grew more intense, as if it could disintegrate at any moment.
Just as the fourth second began, the energy balance at his fingertip completely collapsed. A faint but deadly wave of annihilation energy backfired, racing along the kunai toward his hand.
Alarm bells blared in his mind. Without a second thought, he instantly cut off all energy supply and simultaneously let go, throwing the kunai away.
The tip of the practice kunai in his hand had already, the moment he threw it, turned into a small pile of black ash, scattering in the wind.
Roy looked at his unharmed fingers, his heart pounding with lingering fear.
The limit was three seconds. Beyond that time, even the weapon acting as the carrier would be eroded and erased from within by this power.
This was an extremely dangerous signal, meaning Thunder Annihilation was a double-edged sword. While harming the enemy, it also mercilessly damaged the weapon.
If he had reacted a moment slower, what might have vanished now could have been half his palm.
He would need a tougher, higher-quality carrier.
Ordinary steel simply couldn't withstand this power for long.
After an afternoon of repeated testing and exploration, Roy gained a preliminary understanding of his trump card, Thunder Annihilation.
First, its power was controllable, but directly proportional to his own consumption. Given his current total chakra capacity, he could probably use a full-power strike twice before being completely incapacitated.
Second, its duration was extremely short. The safe limit was three seconds, after which it would backfire on the weapon, and even the user.
Third, the activation process demanded immense mental focus; the preparation time was far too long to be used in the rapidly changing flow of real combat.
So, for now, it wasn't a conventional weapon, but a deeply hidden, one-time trump card not to be used lightly.
A sure-kill card, potent enough to pierce any defense at the most critical moment.
Roy sat beside the rock, now riddled with holes, lost in thought.
The power was sufficient, even exceeding his expectations. The key now was no longer increasing power, but improving control.
He thought back to the leaf exercise in class, which required the most delicate chakra control, demanding the user achieve a state of unity between mind and spirit.
What about Thunder Annihilation?
Could he also exercise such delicate control over this violent power?
For instance, instead of concentrating it for a point-blank burst, could he spread it like flowing water, forming a thin, sustained energy coating on the weapon's surface? That would greatly enhance both duration and flexibility.
This thought made his heart beat faster.
He knew this would be extremely difficult, like teaching a tiger to embroider, but he had to try.
He picked up the last intact kunai, closed his eyes, and once again entered that highly focused state of selflessness.
He constructed the chakra circulation, awakened the Armament Haki, and guided the two to combine.
This time, his intention wasn't to thrust, but to cover.
He tried to guide the formed Thunder Annihilation power, making it spread from the tip of the kunai across the entire blade.
Boom!
An energy clash far more violent than any previous attempt exploded within his palm.
Thunder Annihilation instantly spiraled out of control, and the chakra cage shattered on the spot.
The kunai in his hand didn't last even a single second; from tip to hilt, it completely turned into black ash, dissipating into the air.
A wave of paralyzing, excruciating pain shot through his right arm like an electric current, causing his entire arm to lose feeling instantly.
Roy crashed heavily to the ground, his vision going black. This time, it took him a long while to recover.
He looked at his empty right hand, then at the pile of ash on the ground, the symbol of complete failure. There was no discouragement on his face.
He simply confirmed once more that this path was even harder to traverse than he had imagined.
The sky was growing late. Today's training ended here; his body and mind had reached their limit.
He packed up his things, carefully erased all traces, and left.
Returning to his apartment, he didn't immediately rest.
He picked up a withered leaf that had drifted in through the window sometime earlier and placed it on the back of his hand.
He closed his eyes. He didn't mobilize chakra, nor did he touch the Armament Haki.
He simply used his purest mental focus to perceive the leaf's weight, its texture, and every subtle sensation of its contact with his skin.
To master thunder, one must first be able to lift a feather. One must eat meals one bite at a time, and walk the path one step at a time.