The Heian period of Japan is considered the time when Youkai were most active.
Among them, the most common were the Oni—purely evil Youkai who slaughtered without hesitation and had a particular fondness for alcohol.
Naturally, their favorite drink was brewed from human bones.
Because of this, people of that era lived in fear whenever Oni were mentioned, especially the most terrifying one, who led the rest of the Oni—Shuten Douji, along with his two Oni subordinates, Ibaraki Douji and Hoshikuma Douji.
Aside from Oni, there was another creature that brought disaster to the imperial court—a nine-tailed fox named Tamamo-no-Mae. She was cunning and deceitful to the point where she manipulated the entire court, bending it to her will.
No one truly knew her real face, and those who had seen it and escaped described her appearance differently.
The mystery deepened as noble young women from prominent families started disappearing without a trace.
To humans, Youkai were nothing short of creatures from hell—vicious, heartless, and viewing humans as nothing more than food to be savored.
...However, there was one exception.
In the eastern regions of Japan, instead of fearing Youkai, the people worshipped and remembered them.
This was because a certain Youkai clan existed there—one that did not follow the typical nature of Youkai at all.
In fact, they were known to roam the streets at night, saving countless lives during their "nightly strolls."
According to witnesses, many Youkai followed behind a single figure, shrouded in a mystical, eerie mist.
It was believed that this leading figure was their leader, but no one knew what they looked like.
What was known, however, was that this Youkai had a rather... peculiar personality.
This leader had a habit of sneaking into people's homes to drink sake and eat dango, as if it were their own house.
But since they never caused harm and would vanish whenever people noticed something was off, they were more of an enigma than a threat.
While the leader seemed carefree, their followers were much more dangerous—so much so that the damage they caused was significant enough to be recorded in historical accounts.
Malevolent Youkai hesitated or even trembled in fear when speaking of them, yet many also admired them and wished to follow in their footsteps.
Although history has little record of them, humans knew one thing for certain—their clan maintained balance between humans and Youkai.
And so, a name was given to the phenomenon that occurred whenever this clan took to the streets at night:
Hyakki Yagyō, the Night Parade of a Hundred Demons.
...Until the Edo period, when the leader of the Hyakki Yagyō was finally identified and given a name—
Nurarihyon.
***
"Do you have a wife? Do you have a girlfriend? Do you like energetic girls? Do you want to do a Mana transfer with me?"
"Master, just because I allow you to ask whatever you want doesn't mean I'll answer."
"Oh~ how rude~ but I like it!"
"Great, the one and only Master of Chaldea is just a hopeless pretty-boy simp who threw away all shame," Olga muttered, covering her face, while Mash tried to comfort her.
Nura looked at his Master, Gudako, who was utterly obsessed with him, and could only let out a wry smile.
He knew all too well how his face was practically a weapon capable of piercing a maiden's heart with ease.
That same face had helped him win over subordinates without much effort—though, at times, it also brought unnecessary trouble.
After all, his type was gentle, kind-hearted women, not girls who clung to him like glue. (RIP Gudako.)
"Ah! Undead are appearing again! And that creepy-looking hand thing coming out of the ground!!" Olga pointed at the enemies.
"Master, step back. I'll handle this," Nura said, drawing his katana.
"I-I can help!" Mash insisted, stepping forward.
"You step behind me."
"W-What? Why?!"
"You're weak."
"B-But I have a shield! I can take hits!"
"Mash, shield or not, it doesn't matter. Stay behind me. A subordinate shouldn't stand in front of their leader."
…Excuse me? Subordinates in the back while the leader goes first?!
"Besides, you're a girl, and I don't like seeing girls get hurt in battle."
"But—"
"No need to worry. You don't have to prove yourself useful. You can always rely on me because I allow it."
Wow. Smooth talker. No wonder he had a whole fanclub of women chasing after him.
Hearing Nura's words, Mash reluctantly stepped back. But the moment she did, an odd sensation washed over her, filling her with an inexplicable confidence. She glanced at Nura's back.
For some reason, just looking at him gave her absolute trust—a trust so overwhelming it felt like he could even slay a god.
At that moment, Nurarihyon smiled.
[EX Skill: The follower of Hyakki Yagyō]
As long as you follow the leader of the Hyakki Yagyō, your morale will skyrocket. Youkai, in particular, gain a 30% boost in power.
"So, how does it feel?"
"H-How did you do that?! I feel ridiculously confident!"
"I'll take that as a thank you."
"STOP TALKING AND START FIGHTING!!!" Olga yelled.
Oh, right.
"I'll handle that hand thing," Nura said, casually walking forward.
"Nurarihyon-san! That hand might be a Caster! Please be careful!"
The hand fired a blast of magic at Nura.
The moment the attack hit him, his entire body dissolved into black smoke and vanished.
Then, in an instant, he reappeared right behind the magic-wielding hand and sliced it clean in half with a single powerful strike. Without missing a beat, he rushed forward, cutting down the undead with ease.
Mash could only stand there, watching in awe.
"So this is what it feels like to have a strong Servant at the start of the game. Damn, this is easy."
"What the hell are you talking about, Fujimaru?"
"Yawn…"
"I hate you. You sleepy dumb."
Once the battle ended, the four of them stopped near a bridge.
"YOU—DID YOU FORGET EVERYTHING I TAUGHT YOU?!"
"Nura! Olga's bullying me!!"
"YOU THINK HIDING BEHIND YOUR SERVANT MAKES YOU SAFE?!"
"Stop fighting, you two!"
Olga huffed and glared at Gudako.
"Do you even know what a Servant is? Don't tell me you don't!"
"Uh… well… the characters I roll in gacha? I dunno."
"…Servants are Heroic Spirits. They're legendary figures from the past (maybe) who become allies through a contract."
"WHAT?! YOU'RE TELLING ME MY NURA IS A HERO?! I LOVE HIM EVEN MORE!!!"
"SHUT UP AND LET ME FINISH EXPLAINING!!"
As the two of them bickered, Mash noticed Nura casually pulling out a smoking pipe from somewhere, watching them with the most relaxed, indifferent look possible.
"You look… oddly used to this."
"Yeah. My subordinates were always loud, so I'm used to it. Seeing you two act like this kinda reminds me of them."
"Then… I hope you can meet them again… somehow."
"Haha, it's fine. I'll see them again—I know I will."
The two continued watching Olga and Gudako yell at each other, unaware that someone was watching them from afar.
*****
This story of Nurarihyon is not canon (i mean, is fanfic), so I can do anything about it but don't worry, I won't change too much