Being transported to an unfamiliar era inevitably meant that things and people had changed.
When he first crossed over, he was merely five years old. Aside from knowing his name was Kaigaku, he knew almost nothing else.
Both his parents were dead, leaving him an orphan. He wandered the streets all day, sometimes getting a full meal, sometimes going hungry—his situation was rather miserable.
However, Kaigaku's soul was, after all, from a later time. Relying on his wits and resilient willpower, he somehow managed to survive in Japan's Meiji era.
As he grew a little older, Kaigaku originally planned to use his advanced knowledge from the future to build a fortune and make a name for himself. Little did he expect that reality would slap him hard in the face!
It happened one night when he was sixteen.
That day, to earn a little extra money, Kaigaku was returning home very late. As it turned out, walking too many night roads, he actually encountered a demon!
A real demon! A man-eating demon!
A terrifying monster with blue skin, fangs, and a hideous appearance that only came out at night to feast on human flesh and blood!
Facing this ferocious demon, Kaigaku had nowhere to run. His soul was nearly scared out of him! His heart filled with sorrow and despair: 'Could it be that I, Kaigaku, a proud transmigrator, am going to meet my end before I've even made my mark!?'
'No way!'
As if heaven heard his plea and his unwillingness, just as Kaigaku was about to be devoured by the demon, a spirited old man descended from the sky! In his hand was a samurai sword shimmering with lightning, and with one stroke, he severed the demon's head! The man-eating demon turned to dust!
At that moment, Kaigaku sat on the ground, watching the faint traces of lightning encircling the old man, his mind completely short-circuiting.
First man-eating demons, now lightning samurai... the world he had transmigrated into was clearly not some ordinary place. It seemed he had crossed into an extraordinary world!
Wait! Demons? Lightning? A little old man? Me... Kaigaku!?
Putting all these pieces of information together, Kaigaku finally realized which world he had transmigrated into!
This world was the world of Demon Slayer! And he was that despicable, scumbag traitor who deserved a thousand cuts!
Once he understood, Kaigaku's feelings were simply indescribable.
In Demon Slayer, there were countless villains, and many of them had tragic pasts. While their crimes were unforgivable, their circumstances could evoke some pity.
However, there were also a few villains who absolutely had to die, scoundrels who needed to be nailed to the pillar of shame!
Unfortunately, Kaigaku was one of them.
In the original story, Kaigaku, an orphan, survived by drinking muddy water and stealing, gradually developing a selfish, self-serving personality that only considered his own interests.
Later, Kaigaku was taken in by Gyomei Himejima and raised in the temple. Unfortunately, he didn't change his ways. After being driven out of the temple by the other children for stealing money, that very night, Kaigaku encountered a demon on the mountain. To save his own skin and get revenge on the other children, he sneaked back into the temple, extinguished the wisteria incense burner Gyomei had lit inside, luring the demon into the temple, and used the chance to escape himself.
All the children in the temple except for the four-year-old Sayo were killed. Gyomei fought the demon desperately to protect Sayo until dawn, finally destroying it. Kaigaku's actions indirectly led to Gyomei being wrongly imprisoned.
When he was older, Kaigaku apprenticed under Jigoro Kuwajima to learn Thunder Breathing. He never shed his selfish nature, jealous and disdainful of his junior, Zenitsu Agatsuma, often bullying him.
After joining the Demon Slayer Corps, Kaigaku didn't get along well with other members either. During one battle, he encountered Upper Rank One, Kokushibo. Without an ounce of backbone, he knelt and begged for mercy, was half-forced, half-willingly drank demon blood, turned into a demon, and betrayed the Demon Slayer Corps! Betrayed humanity!
Because of this, his master, Jigoro Kuwajima, who had painstakingly raised Kaigaku, had no choice but to commit seppuku to atone for the disgrace.
Finally, during the decisive battle in the Infinity Castle, the selfish and arrogant Kaigaku was slain by Zenitsu Agatsuma, ending his sinful life.
Looking at his entire life, it's clear that Kaigaku is one of the very few villains in Demon Slayer who is completely irredeemable and utterly unforgivable!
Thinking of this, Kaigaku felt a wave of despair.
Was he destined to live this second life scorned by all!?
No! Absolutely not!
Since I have crossed over, I will change this wrong life!
Since I have crossed over, it means these future events will not happen!
Kaigaku's eyes grew determined. He climbed to his feet and stood up, looking at the energetic old man before him.
Holding a Nichirin Blade, using Thunder Breathing, with graying hair and a distinctive mustache, a cane in his other hand, one leg being a prosthetic—though his face was aged, his spirit was as vigorous as a young man's.
No mistake.
With such obvious characteristics, he must be the former Thunder Hashira of the Demon Slayer Corps, the current Demon Slayer trainer, Jigoro Kuwajima!
He's a powerful ally! I need to latch on to him!
Setting aside any pretenses of pride or aloofness as a transmigrator, Kaigaku bowed respectfully to Kuwajima:
"Thank you for saving my life, sir!"
As if by some divine providence, Jigoro Kuwajima looked at the boy before him, especially noting the determination in his eyes, and found him quite agreeable.
"Boy, what's your name?"
"My name is..." For a moment, Kaigaku hesitated.
The character for 'Kai' meant cunning, deceitful—perfectly matching his original sinful, mistaken life!
He didn't want to be Kaigaku anymore!
He wanted to change!
He made a swift decision and answered Kuwajima with firm resolve:
"My name is Horigaku! Yes! That is my name!"
"Horigaku, huh? That's a fine name..." Kuwajima grew even more appreciative of the lad. "Young man, would you like to become my disciple? Learn my skills?"
That was exactly what he wanted to hear!
Horigaku was almost overjoyed. He replied without a second thought:
"I would! Sir! No! Master!"
The word "Master" instantly touched the kind-hearted old man.
Jigoro Kuwajima seemed almost surrounded by blooming petals.
After a brief moment of emotion, he quickly reined in his somewhat childish side and became serious again:
"Is that so? Think carefully. My skills are not easy to learn. And once you master them, you must shoulder the corresponding responsibilities."
Horigaku did not waver, his expression still firm:
"I've thought it through. Sir, you must be one of the legendary Demon Slayer swordsmen, right? I am willing to learn from you! I am willing to slay demons and protect humanity!"
Seeing him so eager, Kuwajima couldn't maintain his reserve any longer.
He laughed heartily, so happy he seemed beside himself, feeling more and more that this boy suited his tastes perfectly.
He kept patting Horigaku's head:
"Hahaha... Good lad! From now on, I am your master! I will definitely pass all my skills on to you! Make you the strongest Demon Slayer swordsman! Hahaha..."
Although he had some understanding from the original story, experiencing such close contact, Horigaku needed a moment to get used to Jigoro's intense affection. He smiled wryly:
"Master, I understand how you feel, but could you please stop ruffling my hair? You're turning it into a bird's nest..."
"Hahaha... What does it matter?"
"Master! Composure! Composure! Calm down!"
And so, Horigaku, who had been alone and adrift since crossing over, was formally taken in by Jigoro Kuwajima.
He brought him back to his secluded home on Peach Mountain to live together, where he would be properly taught and trained.
Horigaku did not disappoint Jigoro Kuwajima's expectations.
With his intelligent mind, natural talent, and exceptional physical aptitude, he thirstily absorbed knowledge, rapidly tempered his body, and began learning Thunder Breathing step by step.