Back in his room, silence wrapped around Raiden.
"Do you choose to merge?" the system asked.
"Yes."
The answer barely finished forming in his mind before warmth flooded his body.
At first, it was gentle, like heat spreading through his veins. Then it intensified, surging like electricity, flowing through every limb. The first thing to change was his comprehension.
Raiden felt as though something inside his mind had been cleared away. Thoughts sharpened. Confusion vanished. Ideas that once felt distant suddenly became obvious.
His understanding of Thunder Breathing, something that once felt unreachable, became clear in an instant.
It was like stepping out of thick fog and realizing the path had always been there.
Next came the change in aptitude.
Raiden felt it immediately. His body loosened, his muscles responding faster, more precisely. Every breath felt different, as if the air itself carried energy he could now sense.
His movements became lighter. His limbs obeyed his intent without delay.
A faint crackling sound echoed from within his body as he shifted his posture.
Raiden clenched his fists, stunned.
If he had possessed this aptitude before, even mastering several Thunder Breathing forms would not have been difficult.
Then came the talent integration.
Talent was something rare even within the Demon Slayer Corps. As far as Raiden knew, only Zenitsu and Tanjiro Kamado possessed such innate gifts.
When Zenitsu's Echoing Hearing merged with him, Raiden felt warmth spread through his ears, followed by a brief dizziness.
When the sensation faded, the world changed.
He could hear distant sounds with startling clarity. The faint rustle of wind in the courtyard below, footsteps far beyond the walls, even the subtle shift of wood settling in the house.
Raiden closed his eyes and focused.
Every sound carried emotion, intent, and detail.
Echoing Hearing was not just heightened hearing. It was awareness.
Finally, the system integrated the skill.
Thunder Breathing First Form, Thunderclap and Flash.
Pain struck instantly.
Raiden felt as though lightning surged through his body, sharp and overwhelming, before settling into something stable and controlled.
A strange connection formed, as if his body now understood lightning.
He lifted his hand.
Golden sparks leapt between his fingers.
Picking up the training sword beside his bed, the arcs traveled along his arm and wrapped around the blade. Power hummed beneath the surface, restrained only by his control.
Raiden held his breath.
If not for fear of alerting Jigoro, he would have tested the technique immediately.
Once the integration finished, Raiden checked his status.
Host: Raiden
Race: Human
Rank: Mizunoto
Comprehension: Upper
Aptitude: Upper
Talent: Echoing Hearing
Skills: First Aid and Bandaging, Proficient
Thunder Breathing First Form, Thunderclap and Flash, Proficient
Raiden exhaled slowly.
"No wonder," he muttered.
Zenitsu had reached Hashira-level strength in less than two years. With this foundation, it made perfect sense.
And this was only Upper level aptitude and comprehension.
Raiden could not imagine what Super level would feel like.
Within the Demon Slayer Corps, Muichiro Tokito possessed the most terrifying talent. After becoming a swordsman, he reached Hashira level in just two months.
If Raiden could form a bond with someone like him, his growth would be absurd.
That thought made him pause.
He remembered the system's rules.
Friendship levels determined the number of rewards.
The system responded immediately.
Friendship Levels: Acquaintance, Friend, Close Friend, Best Friend, Soulmate
Each level grants one reward
Maximum rewards per person: five
Understanding settled in.
Raiden removed his outer garment and sat on the bed, steadying his breathing as he adjusted to his new body.
The next morning arrived quickly.
Jigoro's familiar shouts echoed through the mountain, followed by Zenitsu's dramatic wailing.
At first, Jigoro had attempted to train Raiden as well. After realizing Raiden lacked talent, he stopped forcing the issue and allowed him to train at his own pace.
Normally, Jigoro would drag Zenitsu straight to the back mountain, ignoring his complaints.
Today was different.
Zenitsu was sent alone.
The moment Jigoro told him to train by himself, Zenitsu's crying stopped.
Alone meant opportunity.
The instant he stepped outside, Zenitsu bolted down the mountain at full speed.
Inside his room, Raiden's ears twitched.
Jigoro had stopped at his door.
Raiden stood and opened it.
Jigoro tapped his cane against the ground. "Come out. We need to talk."
Raiden nodded. He already knew what this was about.
They stopped in the middle of the courtyard.
"Do you know why I brought you and Zenitsu here?" Jigoro asked.
"To train us and prepare us for the Demon Slayer Corps," Raiden replied.
Jigoro nodded. "The Final Selection is approaching. Zenitsu will participate tomorrow. As for you…"
He did not finish the sentence.
Raiden understood.
Given his previous lack of strength, preventing him from attending was an act of protection.
In that selection, over twenty candidates entered. Only five survived.
Everyone else died.
But Raiden was no longer the same.
With the Friend System, his growth would rival even Muichiro Tokito, possibly surpass it.
This opportunity could not be ignored.
"Grandfather," Raiden said calmly, "I want to participate."
Jigoro turned sharply, surprise flickering across his face.
Raiden was mature, sensible, far more grounded than Zenitsu or Kaigaku. He should have understood the danger.
"This is not a game," Jigoro said bluntly. "With your strength, entering the Final Selection is suicide."
Raiden did not argue.
He picked up the training sword at his side.
Closing his eyes, power surged outward.
Golden lightning crackled around him, sharp and vivid, dancing along the blade.
Raiden knew revealing this strength was abrupt.
But to enter the Final Selection, an approval was required.
Jigoro froze.
His eyes widened as his grip tightened around his cane.
As the former Thunder Hashira, he knew exactly what he was seeing.
But the question burned in his mind.
Why was Thunder Breathing appearing on Raiden, a boy who should have had no talent at all?