Why Fushimi Gaku Became the Demon Lord: The Last Boss's Justice
A major incident shakes the virtual streaming world. Fushimi Gaku, a popular VTuber from the second generation of Nijisanji, suddenly stops all broadcasts. The only official word is an indefinite hiatus. No reason is given, and his presence slowly fades from fans' memories. But in a place no one knows, Gaku is caught up in a different battle.
It begins with a single message from a girl named Miyako. She confesses that her older brother has gotten involved in illegal modification streams behind
Why Fushimi Gaku Became the Demon Lord: The Last Boss's Justice - Deep web stream — In the eyes of the senior who was once kind, a fleeting glimmer of "help me"
Akihabara at night breathes differently than it does by day. The more garishly the neon of the main street flickers, the deeper the back alleys sink into shadow. Fushimi Gaku pulled the hood of his black parka low over his eyes and walked along a route that kept him in the shadow of a mixed-tenant building no one ever approached.
The damp July air clung to the nape of his neck. It wasn't sweat. It was something else, something that seemed to crawl across his skin.
(So this is the place.)
Gaku glanced at his phone screen. An infiltration route introduced to him by another Liver from Nijisanji. On the outskirts of Akihabara, behind an electronics megastore, stood an old mixed-tenant building. In its basement, they said, was Nocturne's deep-layer streaming studio.
The name of his contact was something he'd promised never to speak aloud. He couldn't drag someone who'd trusted him into danger. He would take only the information, and from there, verify everything on his own two feet.
The building's entrance had its shutter half-lowered. Gaku ducked under it. A corridor lit by flickering fluorescent tubes. The paint on the walls was peeling, and exposed wiring hung down from the ceiling.
Following the emergency stairway signs, he found the staircase leading underground.
One step down.
The sound of his soles scraping concrete echoed with unnatural loudness. Two steps, three. With each descent, the air changed. Different from the lukewarm air above ground — this was cold and stagnant. Mold and machine oil and something sickly sweet, all mixed together.
And then, sound.
From beyond the wall, a low, undulating noise leaked through. At first he thought it was the air conditioning. But it wasn't. It was human voices. Many voices, overlapping, distorting against each other, merging into a single mass that made the walls tremble.
Gaku stopped.
(Streaming audio.)
Deep in his chest, something pulsed violently. Sweat seeped into his palms. He gripped his phone tighter. His fingertips were trembling, just slightly.
He was about to step into a territory from which there was no turning back.
Gaku understood. Beyond this point, he was no longer in the domain of "a college student acting on a sense of justice." This was the deepest place of a dark organization called Nocturne. And he was about to walk in alone.
(But I'm going anyway.)
Miyako's face surfaced in his mind. The girl who, in a café in Akihabara, had spoken about her brother in a trembling voice. The seventeen-year-old who'd offered him onigiri and fussed over his health, acting like a big sister.
"Please save my brother."
Those words had been pushing him forward.
Gaku reached the bottom of the stairs. He stood before the door leading underground. A heavy iron door. Its surface was covered in countless scratches, and only the handle was strangely worn down. Proof that many people had passed through this door.
Gaku took a deep breath. His lungs filled with the cold air.
He pushed the door.
Slowly, without making a sound.
Light leaked through the gap. Pale, fluorescent light. And the streaming audio he'd been hearing through the wall became suddenly, sharply clear.
"You've gotta be kidding me! Do you have any idea how much I stream for you people?!"
A man's shouting voice. An unnaturally flat quality, as if passed through a speaker. Only the emotion was swollen beyond what was necessary.
Gaku peered through the gap in the door.
The underground studio was larger than he'd expected. In a space about the size of two school classrooms, streaming booths were lined up in rows. In each booth sat a single streamer. All of them wore headsets, all of them talking endlessly at their monitors.
"Just do what I tell you! If you've got complaints, leave your money and get out!"
Another shout from another booth.
"I can't do this anymore... No one ever looks at me... Please, someone... someone, please need me..."
Crying. Sobbing, amplified through microphones, echoing through the entire studio.
Gaku was speechless at the sight.
Every one of the streamers' faces was smiling. Only their mouths were curved upward, like manufactured things. But their eyes were different. Every streamer's eyes were hollow, reflecting nothing. The emotion amplification filter had forcibly suppressed their tears and fear, leaving them smiling as they spewed abuse and whimpers.
It was as if dolls with their emotions extracted were speaking in recorded voices.
Along one entire wall of the studio, large monitors were installed. On them, each streamer's data was displayed in real time.
〈Streamer ID: No.047 Dependency Score: 8.2 Personality Overwrite Progress: 47%〉
〈Streamer ID: No.112 Dependency Score: 9.7 Personality Overwrite Progress: 71%〉
〈Streamer ID: No.003 Dependency Score: 9.9 Personality Overwrite Progress: 92%〉
The numbers updated dispassionately. Human minds, managed and consumed as numerical values. The scene was unlike any streaming site Gaku had ever seen.
This wasn't streaming.
This was exploitation.
Gaku spotted a certain name displayed on the monitor, and his breath stopped.
〈Streamer ID: No.003 Ayatsuji Minato Dependency Score: 9.9 Personality Overwrite Progress: 92%〉
Minato.
Ayatsuji Minato.
Gaku's eyes froze on that name.
(92%.)
He already understood what the number meant. The application rate of the personality overwrite module. Over ninety percent of Minato's personality had already been replaced by "something else" that Nocturne desired.
What remained was a mere 8%.
(There's still time.)
Gaku bit his lip. The taste of iron spread through his mouth.
At that moment, another voice came from the back of the studio.
"Oh my, how unusual. Are you lost?"
Gaku's body went rigid.
The owner of the voice stood in the central floor.
Backlit by the pale monitor glow, a man was looking at him. A thin body. Gaunt cheeks. Deeply sunken eyes. Only the faintest trace of his former self remained.
It was Ayatsuji Minato.
"Only invited guests are allowed in here. ...Who are you?"
Minato's voice was different from what Gaku had heard through the streaming audio. Lower, colder, flatter. A voice without emotion. Not a human voice — the voice of something else.
Gaku forced out his voice.
"...Minato."
Minato's eyebrow twitched. But there was no reaction in his eyes. He looked at Gaku's face without any sign of recognizing an acquaintance. No — he wasn't even trying to "recognize" him.
"Minato? Ah, you mean the original owner of this body. What a nostalgic name to bring up."
Minato's mouth slowly twisted. An expression impossible to distinguish as smiling or sneering.
"He's not here anymore. What's here is a Nocturne deep-layer streamer. The kind senpai you knew disappeared long ago."
Gaku clenched his fist.
(No. He hasn't disappeared.)
The streaming logs Miyako had sent him. After analyzing that data, he'd learned that Minato's original personality hadn't been completely erased. It was simply pushed down beneath the surface personality.
"Are you really okay with this?"
Gaku's voice echoed through the studio.
"Miyako-chan has been waiting for you this whole time. Your little sister is trying to save you, working desperately all on her own."
Minato's movement stopped.
Just for an instant. Just for a truly, truly brief moment.
"...Miyako?"
That name slipped from Minato's mouth. Something mixed into the emotionless voice. Just slightly, the pitch shifted.
"...I don't know that name."
But the cold voice returned immediately. Minato slowly approached Gaku.
"You've been poking around Nocturne, haven't you. The higher-ups have been in contact. 'Watch out for intruders,' they said. ...I never expected a brat like you to show up, though."
Minato's right hand slowly rose.
"Sorry, but you'll disappear here. Anyone who gets in Nocturne's way gets eliminated, no matter who they are."
Gaku didn't retreat a single step.
(This isn't Minato.)
He knew that in his head. But his body wouldn't move. The person before him was the senpai who'd once laughed with him at the same agency. The gentle man who, at drinking parties, would brag about nothing but Miyako-chan.
"Minato."
Gaku called the name once more.
"Your little sister calls you 'Nii-chan.' She came to me crying, asking me to help you because you'd changed. Because of you, that girl is scared and alone right now."
Minato's hand stopped in midair.
"If you're really Minato, there's no way you'd leave that girl behind."
The sounds in the studio seemed to grow distant. The other streamers' shouts, their crying, the monitor noise — all of it faded far away.
Minato's eyes caught Gaku.
Deep within those pupils, something shone.
Just for an instant. Truly, for the span of a blink.
Deep inside those sunken eyes, a light definitely flashed.
Help me.
A scream that couldn't become a voice.
Gaku didn't miss that light.
(He's there. Minato is still inside.)
Deep in Gaku's chest, something grew hot. Not fear, not anger. Conviction. A fissure had opened between Minato's surface personality and his original personality. That fissure hadn't yet closed.
"...Shut up."
Minato's voice growled low.
"Nothing you say means anything. I am a Nocturne deep-layer streamer. In this place, I'll erase you along with your justice."
Minato lunged for Gaku.
Gaku spun his body around.
"This time, I'm bringing you back. ...No matter what."
Gaku ran back the way he'd come with all his strength.
Behind him, Minato's shout chased after.
"Stop! This intruder! Someone, catch him!"
Men who looked like studio guards burst out from the shadows. Gaku ducked low and slipped between them. He wove through the streaming booths, leaped over fallen equipment, and headed for the underground studio's exit.
Behind him, the sound of something falling. Someone's scream. Multiple footsteps overlapping, closing in.
Gaku gritted his teeth. His lungs burned hot. His heart pounded against his ribs from the inside.
(I'm getting out.)
(I can't get caught here.)
(Not until I save Minato.)
He raced up the stairs. One step, two, three. He grabbed the handrail to steady himself as his legs threatened to tangle. The light leading to the surface drew closer, bit by bit.
Gaku burst out of the building.
The night air seeped cold into his overheated body. Gaku ran without looking back. Through the back alleys, out to the main street, melting into the crowd. Tourists' laughter, shop hawkers, neon lights. All of it was a different world from the underground studio he'd just left.
Gaku hid in the shadow of an alley and exhaled raggedly.
He took out his phone. His hands were shaking so badly he could barely open the screen.
One new message had arrived.
Kuronagi Ren.
The person who'd sent him that warning message.
〈You've stepped too far into the deep layer. The higher-ups have made their move. Go into hiding tonight.〉
Gaku stared at the words.
(The higher-ups have made their move.)
In other words, Nocturne's executives had become aware of Gaku's existence. If he continued his investigation, there was no guarantee he'd survive.
Gaku typed a reply to Ren.
〈I want to save Minato. Do you know how to release the personality overwrite module?〉
Sent.
A few seconds later, it was marked as read. But no reply came.
Gaku next sent a message to Miyako.
〈I met your brother. He's still in there. I'll bring him back for sure.〉
After a while, a reply came from Miyako.
〈Thank you. ...Um, please look at this.〉
Attached was a screenshot of a DM from Minato.
〈Miyako, you come to this side too. It's comfortable here.〉
Gaku gripped the screen.
How terrified must Miyako have been to receive this message. Being invited by her brother to the place that had broken him. Imagining her fear and sorrow tightened his chest.
(I will bring Minato back.)
Gaku sent another message to Ren.
〈I want your cooperation. I need your information.〉
This time, a reply came immediately.
〈Are you an idiot? ...Well, I'm
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