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Part 2 of Gwima-gye Universe
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2025-07-23
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2025-10-18
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Goodnight, Demon King

Summary:

Fate is always a choice, even for a Demon King.

When Gwi-Ma’s existence can no longer sustain itself on stolen lives and hoarded memory, he is forced into rebirth as a human child—the very cycle he once defied as Demon King. Baby Saja is crowned in his place, much to everyone’s surprise. Becoming King, however, is not as simple as he thinks.

As one learns mercy as law and the other learns childhood as penance, the Saja Lords and the Huntrix must decide: how far will they go to keep their youngest from breaking under the weight of kingship, and to stop a child from becoming a monster again?

(This story is set in Gwima-gye, my original world. Gwima-gye is a demon realm shaped by Korean cosmology and xianxia, making it a xuanhuan world. If you’re new to this genre, I warmly invite you to give it a try.)

Notes:

Goodnight, Demon King is the Book 2 of The Deepest Echo (Book 1). (archiveofourown.org/works/67464906)

I recommend reading Book 1 first to grasp the flow of events and worldbuilding here. It serves as the groundwork of the Gwima-gye Universe, laying the mythology and emotional roots that this story now builds upon.

Chapter 1: Our King Behind Bars

Summary:

The Boundary Kingdom takes Jinu.

The Saja Lords chase after him.

Somehow, Baby Saja ends up in prison instead.

Notes:

(See the end of the chapter for notes.)

Chapter Text

It was only a matter of time.

And now the disruption trembles through the rivers of the dead, weaves through the threads of mortal vigor, and settles into the lowest roots of Gwima-gye.

Far above the rupture, under concert lights and a screaming crowd, the Saja Boys perform as though the world has not begun to unmake itself.

(Listen 'cause I'm) Preaching to the choir

(Now) Can I get the mic a little higher?

Gimme your desire

Watch me set your world on fire

You're lost in my daze, yeah, you can't look away (Hey)

No one is coming to save you

Now we runnin' wild

You're down on your knees, I'ma be your idol

No one in the stadium senses their skin prickling, unsuspecting of the vibrations that belong to no mortal craft. But the Boundary Kingdom, from somewhere above the mortal grid, does.

“An abnormal soul harvest again,” an Ahjumma mutters.

“It traces to Gwima-gye,” an Ahjussi replies.

“Specifically…” The Ahjumma’s chin lifts, her ear turning toward the great gates that connect realms, listening to the warp in the river of souls. “Gwi-Ma.”

The crowd does not understand what they are watching anymore:

A minute ago, the Saja Boys were dancing under stage lights. And not even another minute to spare, a flash of cyan light slashed across the throne, humming with resonance sharp enough to cleave the night in two. It was Rumi’s sword, conjured from pure spirit power.

The blade carved into the throne’s base, splintering it with a cry that felt ripped from the void itself. Shadows shrieked as they tore away from the structure, and for the first time, Gwi-Ma’s voice cracked.

How dare you—

The force of the slash made a crown slip from a king’s head.

In that shudder of light, Gwi-Ma fell from a world-devouring sovereign to a soul meeting the same nothingness he had forced upon others. The memories he had stolen fled him like birds escaping a cage, and the darkness that once heeded his call broke free at last, leaving him with nothing that was ever his.

And the Saja Lords felt a sudden lightness inside them. The impossible sensation of not being owned. A freedom so foreign it felt like stepping out of someone else’s shadow.

Their attention landed on Jinu, who watched it all with a calm face. The other Saja Lords were ready to leap in, but Jinu meekly stepped forward first. His hands rose, wrists turned outward, palms open. A gesture of surrender no Saja Lord should ever need to make, yet his expression was peaceful in a terrifying way.

“Hyung?” Confused, Baby Saja whispered. "What are you doing?"

Jinu’s voice was soft. “It’s done.”

Before the dust from Rumi’s strike could even settle, three figures appeared, dressed in white robes with pale jade ornaments belonging to the Boundary Kingdom. Their presence felt like neither life nor death.

There was no fear in Jinu, whether from leading the Saja or from having walked toward this moment his entire life. The crowd before him witnessed only the worn curve of his smile, the weary acceptance of finally stepping into the ending he long understood would be his. He extended his wrists further, presenting himself for chains that had yet to form. “Take me,” he declared.

The representatives of the Boundary Kingdom nodded once. And with a sweep of their sleeves, Jinu was gone.

The space where Jinu stands is now empty.

࿐❀𖤓࿔*❅༄

“Wait.”

It is Baby Saja who speaks first with a hushed voice barely audible through the hum of residual resonance. “What do you mean take me?” He steps toward the space Jinu has vanished from, fists balled at his sides. “What do you mean it’s done?”

The crowd still cheers in the distance, blissfully unaware of what they have just witnessed.

“He left,” Abby mutters, eyes fixed on the empty space. “He really just left.”

Mystery’s voice drops. “He must have planned this.”

Baby Saja’s breath comes in short bursts. “If he planned this, why didn’t he tell us?" The question drags his eyes down to his arms, where the demon marks flicker with a dim, ownerless glow, no longer wired to a will that towered over their lives.

He hops once.

It's light.

He jumps again, higher this time.

Still light.

It isn’t his body that feels different, but his soul. It feels light. Unbelievably light. As though the leash that bound them all to the demon king has snapped.

“He’s gone,” he whispers, disbelief hollowing his voice. “Gwi-Ma is really gone.”

Which only means, I’m my own person now.

He spins on his heel. “We're going after Jinu-hyung.”

“Into the Boundary Kingdom?” Abby blinks. “That’s a cosmic jurisdiction—”

“We’re storming it,” Baby Saja declares, golden eyes flashing. “No one kidnaps Jinu-hyung and gets away with it. Not even the law.” He flicks two fingers sharply. “Huddle. Right now.”

The Saja Lords step in without hesitation, shoulders almost touching. Baby Saja glides one foot across the surface, sketching a circle around the group.

“Focus your mind toward the Boundary Kingdom,” he says, tone succinct. “I don’t know its exact location—so we aim for the pull.”

Romance squints. “The pull of what?”

“Of Jinu-hyung's soul,” Baby Saja answers, as if it should be obvious. He levels a look at Romance. “You’re a soul messenger and you’re still asking?”

Romance only shrugs, unbothered by the habitual sarcasm. “It could be anyone from there. Those three from earlier, for example?”

Abby turns toward him. “Wait—can that actually happen?”

Romance taps his chest with two fingers. “Soul tracking doesn’t fade unless we want it to. Although, the tricky part is…” His mouth quirks. “It’s exhausting to track souls that aren’t from Gwima-gye." A soft huff. "I tried it earlier since we finally got to meet beings from another realm."

Mystery considers this, then nods. “He’s right. Marking a soul should be easy for us. The only gap is spiritual reach.” He gestures toward Abby. “Among us four, Abby-hyung has the most demonic years.”

Abby steps forward confidently with a silly grin on his face. “About at least four hundred.”

Baby Saja stares at them, his expression bordering on offended realization, that smile further aggravating the offense. “You’re all quite something.” His thoughts are almost visible as he mentally counts the years.

And right, I'm the only one here with around two hundred…

A scowl threatens. He's not only the youngest in demonic age, but the lowest in cultivation among them. A Heart Immortal Demon, low-tier as the rest, except he sits at the very bottom of that tier. The weakest Saja Lord, technically. But true enough to irritate him.

How could it be otherwise? Their former king had corroded Gwima-gye into the most stagnant realm in the cycle, hoarding memory and starving every demon of progression so his dominion remained absolute. A kingdom suffocated for one creature's desire, making progress a luxury never allowed.

He opens his mouth to complain about Gwi-Ma, when his vision catches on the Huntrix at the center of the stage, interrupting his train of thought. They stand beneath the roar of a crowd still blissfully unaware of the calamity that nearly unfolded. Rumi in particular is too infuriatingly composed, the applause washing over her as if Jinu was not taken at arm's reach. For someone entwined with his hyung’s fate, she seems unreasonably calm.

A suspicion grazes the back of his mind, but dismisses it with a swift thought.

We're different, after all.

He recovers with authority. “Now focus on Jinu-hyung alone before we get thrown off.”

Abby moves to his side. “I’ll stabilize the direction. You aim for him.”

Magenta smoke flurries beneath Baby Saja's feet, then spreads outward around their ankles, spiraling tighter. They brace as the ground reorients them toward an unseen door. A rush of force whirls around them as they gather close, four demons aiming their will toward a realm none of them have ever touched, navigating instinct more than knowledge. They gain freedom, and this is the first thing they do with it. The world rewrites itself around their resolve at once.

No matter the distance, no matter how perilous the path between realms, the Saja Lords will cross it together.

࿐❀𖤓࿔*❅༄

The gates of the Boundary Kingdom simply open. The Saja Lords don't even raise a hand. They just stand there, looking vaguely intimidating under the dim gold light, and the gates part like they have been waiting all along.

“Did we just… win?” Baby Saja taps a lip, attempting to hide his uncouth gaping before the gates. “We didn’t even throw a single punch.”

“Maybe we’re scarier than I thought,” Abby mutters, folding his arms.

“We are,” Romance says proudly, smoothing his robe. “Have you seen us?”

Mystery glances toward the guards who only avoid his eyes as they step aside without a word.

The gates creak open when they descend to the entrance of the dungeon. Even the metal recognizes who they are.

“Wow,” Baby Saja says, wide-eyed. “We didn’t even break anything yet. This is the easiest siege ever.”

They move forward, their footsteps echoing in this kingdom that is all gold and pale jade. Somewhere above the shrouded roofs, a bell tolls.

The Saja Lords are ushered down a set of steps that seem to spiral endlessly. The air grows cooler as they descend further. The guards stop at the lowest dungeon.

“Here,” one of them says.

Baby Saja pushes forward. “Hyung? Did they hurt you—”

The sight of Jinu sitting cross-legged on the cold floor of the cell, head tilted back against the bars, eyes half-lidded, cracks something in them.

Romance breaks first as he grabs the bars. “Oh my god,” he breathes. “Is this the end of everything? Hyung, tell me this isn’t the end. I can’t do this alone.”

Abby just slides down to the floor and presses his back to the bars, his massive frame hunched in defeat.

“Let him go!” Baby Saja yells, spinning on the guards. “He’s innocent! You can’t treat him like a criminal.” His golden eyes blaze with the cries. “If anyone should be locked up, it’s me!”

The guards exchange a glance, then shrug.

“Yeah, you heard me!” Baby Saja yells. “Take me instead!”

And so they do. Two of the guards unceremoniously scoop up Baby Saja under both arms. The cell gate creaks open at the signal of another guard. Jinu steps out, peeking from beneath his lashes, confused like the rest.

“What—” Baby Saja kicks uselessly as they plop him inside. The bars slam shut. “This is not—NO. You can’t just—hey!”

The guards say nothing. They do not even look amused. The Saja Lords just stand there, stunned by the lack of action.

Baby Saja grips the bars, forehead pressed against the cold iron. “Hyungs,” he whispers, voice slightly trembling. “Please… be safe out there.”

The guards turn, escorting the rest of the Saja Lords out.

Abby throws one look over his shoulder. Romance dabs at his tears with a sleeve. Mystery doesn’t even look back.

“HYUNGS?!” Baby Saja shouts, shaking the bars. “You’re really leaving me? At least give me some—HEY!”

The dungeon door shuts with a loud click.

࿐❀𖤓࿔*❅༄

Baby Saja sits on the cold stone floor, one knee pulled up, chin resting lazily on it. He has long stopped yelling for snacks or his hyungs. The silence is suffocating, but he will never give the Boundary Kingdom the satisfaction of seeing him bored. His finger drags lightly across the floor, scratching soundlessly at the concrete. The motion leaves no mark. His mind drifts, to how his hyungs left him behind, to the way everyone seems to be rolling with things he doesn’t understand. No one explains anything anymore. Not the silence, not the plan. Not even the reason he’s here.

Leaning his head to the side, he listens to the slow, echoing clicking of boots. They’re getting closer.

A figure appears. It’s a guard, but not like the rest of the ones who tossed him in here. His uniform is crisp, darker, with pale jade embroidery along the sleeves. He looks like someone who outranks everyone else in the dungeon.

The guard says nothing as he unlocks the gate. The heavy iron door swings open with a low groan.

Baby Saja raises one brow, leaning back slightly. “Not a single announcement?” He pushes himself up. “Where are you taking me?”

The guard does not answer. He turns sharply on his heel and starts walking.

Baby Saja stares after him for a beat, lips curling in annoyance, then follows. His steps are quieter, echoing faintly behind the guard’s boots, amplified by the silence spanning this long hallway lined with white silk that shimmer faintly in the dim light.

He stops walking.

The guard takes a few more steps before noticing, then halts without turning.

“Where are my hyungs?” Baby Saja’s voice is indignant this time. Commanding, even. His demon marks begin to glow, a vivid magenta pulsing beneath his skin. His golden eyes flare brighter in the dim corridor.

The guard turns his head just enough to glance back. His voice is strangely amused. “The Crown Prince of Gwima-gye sure is more restless today.”

Baby Saja’s brows furrow. “Crown Prince? Who?”

The guard sighs, and looks forward again. “Keep walking.”

Baffled, Baby Saja follows anyway, his mind racing, the words crown prince ring in his ears until they start to blur.

࿐❀𖤓࿔*❅༄

The guard stops before a set of tall, looming doors carved from pure jade. Its surface ripples faintly, the light glimmering over as if remembering every soul that has ever passed through.

Baby Saja tilts his head back, squinting. The doors tower so high they disappear into shadow. When they begin to open, the ground rumbles, a deep vibration that rolls up his spine. “Gwima-gye doesn’t even have doors like this,” he mutters under his breath. “This is overkill.”

Just as he is eyeing the massive door from top to bottom, the guard announces in a clear voice,

The Crown Prince of Gwima-gye has arrived.

Baby Saja freezes. He slowly turns his head toward the guard, golden eyes wide with confusion. The Crown Prince of what now?

He says nothing, but his glare speaks for him. The guard ignores it and gestures for him to walk forward.

The main Council hall is enormous. A wide, circular auditorium with high, shadowed balconies. The ceiling is lost in darkness. He cannot see everyone here, but he can feel them: a hundred glowing eyes, a hundred unseen faces. The weight of their attention presses against him.

At the far end of the hall, a woman elegantly stands on the highest balcony. Her hair is silver, long enough to brush the floor, posture straight and imposing. She does not raise her voice, yet it carries through the room.

“We are gathered today,” she says, “to deliberate on the state of Gwima-gye as a realm with a king who desired permanence and dominance. A king who turned himself into a structural heresy against the world’s cyclical order. A king who desired to cultivate a permanent form in a system never meant to preserve identity beyond death.” Her silver gaze sweeps across the room. “Instead of embodying flow, he hoarded memory and tried to freeze what should move. Such a king is a distortion of the natural order. And so, he must undergo tribulations,” she continues.

Baby Saja only narrows his eyes at the glowing entities in the balconies, his hands casually tucked behind his back as he is about to interrogate them. “And what,” he says, voice sharp and clear, “does that have to do with me? And who,” he lowers his chin, “are you calling the Crown Prince?”

A stir runs through the hall. Low murmurs, similar to wind hissing through cracks in a wall.

Figures step out of the shadows behind him. Their presence is familiar.

Baby Saja turns his head, and sees them. The Saja Lords. His hyungs. All of them. His eyes soften for the briefest second. “Hyung?”

Jinu stands at the front. Baby Saja moves to him at once.

“Hyung, what’s going on? Who are these people? What is this place?”

Jinu does not answer, but his eyes stay fixed on Baby Saja.

The woman on the balcony almost resembles a statue as her expression remains unchanging, despite her gaze lowering to Baby Saja. “Jinu’s rebellion has stirred the balance of the realms. His actions forced the eyes of the world to turn toward Gwima-gye, and what we found was a realm enslaved by a king’s hunger.” She pauses. “That hunger cannot be allowed to continue.”

Baby Saja turns to glance at Jinu, frowning. Rebellion? His hyung didn’t tell him any of this.

“What does this have to do with me?” Baby Saja asks again, louder this time. He gestures at himself. “You’re talking about Gwi-Ma, right? Big guy, big teeth, eats everything that moves. Let me tell you, I’m not him.”

The woman shifts her weight, head following the motion. “You are the youngest Saja Lord. The one who resisted Gwi-Ma’s rewriting. You carry memory and willpower strong enough to hold form in Gwima-gye. Do you not see what that means?”

Baby Saja blinks, caught off guard. “What it means is that I’m a really good employee.”

“Crown Prince,” the woman says, ignoring his tone, “you were always next in line. Gwima-gye is without a king. You will inherit its throne.”

“What do you mean,” Baby Saja snaps, whirling around to face the Saja Lords behind him. “Hyungs, you’re hearing this, right? I’m not king material. I’m barely Saja material!”

Mystery’s calculating gaze meets his. Baby Saja hates that look. It makes him feel bare, and anyone will, especially in a situation like this. He spins back to Jinu, panic flashing behind his gold-slit eyes.

“Hyung, say something! Tell them this is stupid. Tell them you’re the leader. Tell them you—”

Jinu just watches him falter.

“Hyung?” Baby Saja’s voice cracks slightly.

The awkward hush that follows burns into him. He swallows hard, then turns sharply to the lady on the balcony, planting both hands on his hips. “Ahjumma, listen here.”

A few of the glowing figures shift at the title, but Baby Saja is too adamant to care. His gold-slit eyes glare straight up at her.

“This crown prince thing? It’s just an inside joke. Please don’t take it seriously.” He jabs a finger at his own chest. “I’m just a good employee. Too good that my hyungs keep saying I’m Gwi-Ma’s crown prince, because I deliver every single time. Souls, errands, tea experiments, you name it.” (Reference: Chapter 4 of The Deepest Echo. If you've made it here without reading Book 1, I suggest checking that out first!)

He crosses his arms, tilting his chin with stubborn pride. “So, unless you’re here to give me actual loyalty points, maybe don’t—”

“Enough.” The woman’s voice cuts clean through the air. Her silver hair gleams faintly as she steps forward, her presence suddenly more foreboding than the entire hall. “Gwi-Ma’s reign has ended. His desire to defy death and bind himself to an identity, is a violation of the world’s cycle. He refused time itself.”

Baby Saja’s smirk falters.

“The king you served must undergo tribulation,” she continues. “He will return to the Wheel, stripped of power, to walk the path of rebirth. What remains of Gwima-gye must have a ruler. One who does not seek permanence, but Balance.” Her gaze locks onto Baby Saja. “That is you. Crown Prince or not, this is your duty. You are the only one who can inherit the throne.”

Baby Saja scoffs at the woman's words. He shifts his weight, crossing his arms. “Yeah, okay,” he mutters, rolling his eyes. “Balance, destiny, blah blah blah.” He turns on his heel and grumbles under his breath as he tugs at Abby’s sleeve. “Hyung, tell her. Tell the ahjumma it’s just a joke. I’m not a crown prince. I’m the Young Saja Lord. You know this.”

Abby just stares at him in silence.

“...Hyung?” Baby Saja’s voice wavers. “Please. Say something.”

That silence hits harder than the strange woman's words. Baby Saja’s shoulders slump, mouth twisting into a pout as he steps away from Abby and trudges back toward Jinu.

“Hyung,” he says, the words coming out faster, panic creeping in. “You gotta tell them. I can’t supervise new spawns forever. I’m not—I can’t—”

Jinu’s gaze softens, but his fingers flex before falling back to his side. “It’s true,” he says, slowly.

Baby Saja freezes, jarred by how readily Jinu concedes to a council they met only today. “Hyung?” His eyes drop to the slight twitch of Jinu’s hand.

Jinu closes in and places a hand upon Baby Saja’s shoulder. His expression stays composed, though his tone draws a firm line. “You’re the one they chose. Whether you asked for it or not.”

Notes:

➴ Xianxia literally means “immortal heroes.” It’s a Chinese fantasy genre deeply rooted in Taoist and Buddhist concepts, infused with martial arts, mythology... and magic! ⋆⁺₊✧ˎˊ-

Doesn't matter if you’re new to xianxia, a casual reader, a master cultivator, or a seasoned celestial already flying on your sword.

I’ve prepared a glossary of terms often used in the Gwima-gye Universe which you can find in the end notes of chapters, to help you follow the worldbuilding more easily. I’ll do my best to keep the explanations simple.

Before any master cultivators jump on me, know that my Gwima-gye Universe does not strictly follow canon xianxia ideologies or systems. I built this world by blending different philosophies from across the globe, so it follows its own path. This makes the Gwima-gye Universe a xuanhuan.

➴ Xuanhuan means “mysterious fantasy,” a broad fantasy genre that borrows ideas from xianxia but is not limited to it. It mixes influences from different philosophies and mythologies, creating its own rules for its world.

Now you know the distinction between xianxia and xuanhuan.

If ever you come across a term that isn’t listed, feel free to drop it in the comments and I’ll be happy to explain.

Welcome to the Gwima-gye Universe, dear cultivators.

࿐❀𖤓࿔*❅༄

Alright, first round of terms!!!

➴ Tribulation: The ultimate trial a cultivator must face when they reach a breakthrough. It tests whether a cultivator is worthy to ascend to a higher realm or being. Passing means advancement in power and lifespan, while failing can cripple or even destroy the cultivator completely... depending on how badly they did.

➴ Gwi-Ma's Tribulation: For him, the whole tribulation process was inverted. Instead of ascension, his tribulation cast him down to a reverse ascension. It's like a demotion haha. But that very fall opened a chance to forge his own mortal path. ❤︎

➴ Balance: The guiding law, the order that keeps realms flowing. It's the cycle of birth and death, light and dark, time and return; the flow that preserves harmony and punishes excess.

➴ Demons vs. Devils: Demons are supernatural beings from nature. Examples of demons can be spirits or fairies. Devils are the truly wicked, the ones corrupted by evil and suffering from moral decay. So basically demons aren’t inherently evil, but devils usually are.

Adding more in the next chapters!