INTRODUCTION: Before The Heat

I love this How It’s Done x Born To Be mashup! The themes of KPop Demon Hunters are a major inspiration for the story. Fun fact: ITZY themselves were one of the inspirations for HUNTR/X!

Jeju Heat began with a single image: desire under bright sun, masks slipping in the dark, and idols learning who they are only when no one is watching. A hot pool scene that accidentally became a deranged story about idol bodies, intimacy, performance, spectatorship, friendship, and getting ruined in a variety of emotionally significant positions.

What started as fantasy became a mirror: one that reflects more than just bodies - the wounds, hunger, and the secret lives behind the spotlight.

In a world of curated perfection, intimacy is the only language left to speak.

On Sex in This Story

In this universe, smut is hot (I hope!), but also does significant narrative work - it is the language these people tell the truth in. The idol system demands bodies be perfected, monetized, disciplined, controlled - so sex becomes the space where characters reclaim agency, reveal vulnerability, or expose wounds the industry demands they hide.

What sex reveals for each character:

• Minho: how he connects and stays close

• Yeji: how she says I need you without admitting it

• Yuna: a battlefield for self-worth

• Ryujin: rebellion against a system that tries to box her in

• Chaeryeong & Sunwoo: devotion

• Lia & Minjun: reality

• Karina: the ache of being pedestalized instead of seen

Everything someone does with their body tells a truth their mind isn’t ready to speak. For some characters, sex is escapism; for others, it’s the only language they trust. For a few, it’s where their real feelings slip out when the masks fall, and the tender, naked self steps forward.

The Characters - A (Not So Brief) Primer

For clarity, Minho, Sunwoo, and Minjun share names with real idols, but in this story they are entirely fictional male characters. Within the narrative, Sunwoo is depicted as an idol, but no real group or affiliation is specified. These characters exist solely for the purposes of this work of fiction.

Minho - the ex-trainee caught between guilt, desire, and love

What if the man built to please everyone finally had to face what HE wants - and whether he is allowed to want at all?

Minho lives in the shadow of a what nearly was: a trainee who didn’t debut. His regret is twofold - leaving that world, and leaving Yeji behind in it. Despite their deep emotional bond and genuine best-friend chemistry, he still feels unworthy of her, like he forfeited his place in Yeji’s sexually charged world of idol politics, and believes himself lucky to have “access” to her at all. He wants to please, attune, give, because it is how he feels useful and needed. Their “friends with benefits” dynamic is a lie they both cling to - for him, out of fear; for her, out of avoidance. His history with Yeji is years-deep, rooted in trauma and in the closeness of two people who leaned on each other in darkness. He’s the only person who ever saw Yeji crack, and that intimacy ties him to her in ways he struggles to define. He doesn’t dare overstep, doesn’t dare assume she wants him beyond the physical, even as he stays tangled in her for years. His guilt - especially after accidentally learning that the pool incident with Yuna/Ryujin was caught on Lia’s camera - shapes much of his internal conflict and pushes him to question what Yeji truly means to him.

Minho’s real superpower, the thing that makes him irresistible in-universe and a subversion of typical self-insert tropes, is attunement. He sees people, not their images or personas. In-universe, this is why his POV is so rich in erotic detail: he notices what others miss. The tremble before a moan, the subtle squeeze with every thrust, the way someone’s mask cracks when they’re touched with care. His gaze is perceptive, not objectifying. He understands each woman differently, honors who she is, and adjusts instinctively - not to dominate, but to give. It’s why everyone ends up having their best sex with him: because he listens, he adapts, he delights in their delight. His pleasure is never self-serving; it’s tethered to their happiness, their unraveling, their being truly seen. In a world full of takers, Minho is a giver; and that kindness, not just his skill, is what makes him dangerous to the women who get close. It’s what made Yeji fall in love without admitting it. It’s what makes Yuna crumble, Karina soften, and Ryujin concede. He is the fantasy of a man who looks at hypersexualized idols not as fantasies, but as humans aching to be understood.

Hwang Yeji - A kitten wrapped in leopard skin

What happens to a girl who was forced to be perfect when she finally meets someone who makes it safe to be messy?

Yeji wears her professionalism like makeup: precise, polished, disciplined, impermeable. She was raised by the industry to be unbreakable - the fierce leader, the responsible unnie, the perfect performer who absorbs pressure without complaint. The result is a mask of dominance and composure that hides a girl who is, at her core, goofy, affectionate, sensitive, and deeply afraid of disappointing the people who believe in her. Her near-failure during training - the D-graded vocal evaluation that almost cost her debut - left a scar she doesn’t speak about. It forged in her an avoidant instinct: don’t rely, don’t reveal, don’t risk losing what you worked for. Relationships feel dangerous not because she doesn’t want them, but because she fears what intimacy might cost.

Minho is the exception carved into her life. They trauma-bonded during training after he held her through a quiet, private breakdown - the first time she ever let someone see her crack. He helped her train, helped her raise that vocal grade, helped her survive. She never labeled what that meant, never allowed herself to examine the tenderness buried in that shared history, but a piece of her heart imprinted on him and never left. She carries gratitude for him like a secret vow: I am here because you were there. In her mind, that debt is sacred - and terrifying.

Avoidant by instinct and perfectionist by necessity, Yeji refuses emotional language, but her body speaks fluently. She expresses affection through physicality: sex, touch, presence. She communicates feelings by clinging to him, teasing him, slipping into absurdly girlfriend-coded behavior without ever admitting why. She becomes territorial without understanding the impulse. She plays, she touches, she gravitates - not consciously, but because happiness turns her soft and unguarded. With Minho she melts fast, submits easily, brightens visibly. Her brain thinks in duty; her heart thinks in warmth she is scared to name.

Her arc is the slow, inevitable unmasking of that real self - the tender, silly, fiercely loving girl underneath the leopard’s posture. Not a tragedy, but a revelation: Yeji is not cold, not detached, not unfeeling; she is simply afraid to hope, afraid to want, afraid to reach for something that could break her if she names it. And Minho, deliberately or not, is the one person who makes her forget she’s supposed to be strong - the one person she instinctively trusts enough to be messy, playful, needy, vulnerable, and real. Her journey is learning, slowly and painfully and beautifully, that the softness she hides is not weakness but truth - and that it is finally, finally safe to tell herself: it’s okay.

Beneath her avoidance, Yeji carries two core fears she has never named: that she is not good enough, and that she will lose Minho again the way she lost him when he quit training. Their shared past created a debt she believes she can never repay and a lost future she grieves without admitting it. These wounds shape the FWB dynamic she clings to: keeping him close enough to feel safe, but far enough that labeling it might make the loss real. This contradiction drives her avoidance and the hidden tenderness that makes her the leader we love and others fear.

Shin Yuna - The siren’s coming-of-age

What becomes of a teenager given the power to seduce the world before she ever learned who she is?

Yuna is both the story’s tragicomedy engine and erotic fireworks show - a girl with the body of a seductress and the unpredictable, emotional wiring of a teenager who never got the chance to grow at her own pace. She is photographed, adored, sexualized, worshipped by strangers… yet still treated like a child by the people closest to her. That contradiction defines her worldview. To her, sexual freedom equals adulthood. Mastering desire, both her own and others’, feels like mastering power. She’s is all about appetite - a little monster with too much beauty and perhaps too little supervision. She plays at being a temptress because it’s the only arena where she feels she can win. But beneath the bravado and thirst-trap confidence lies something far more fragile: she isn’t addicted to sex, she’s addicted to validation, to feeling pretty, chosen, seen, important. Her impulsive hookups, horny spirals, competitive seduction games, and relentless masturbation routines are all attempts to assert control in a life that has always been curated, censored, and infantilized.

Her internal world is loud, messy, self-obsessed, intensely Gen Z: she gets horny at random, hypes herself up in mirrors, scrolls thirst traps like homework, films herself because “future me will be hot,” and treats desire like a sport she’s determined to master. She experiments constantly - pillow humping, frantic edging, sexy challenges from TikTok, chaotic angles that make sense only to her. Her camera roll is a minefield of nudes, eye-candy screenshots, masturbation clips, saved DMs, and even a secret Minho zoom-folder she’d die if Yeji ever found out. She thinks she understands sex and seduction because she can turn men into puddles, treat them like toys, win the game every time. But she has no idea what real intimacy looks like - which is why she misreads, resents, and envies what Yeji and Minho have. She plays with fire believing she’s fireproof, only to learn that the heat she chases can burn.

To her members, she is the beloved chaos maknae - horny, impulsive, adorable, sincere, impossible not to protect. Ryujin mercilessly teases her, Chaeryeong listens with gentle disbelief, Lia has long accepted that her eyes will occasionally witness things they shouldn’t, and Yeji... Yeji is the unnie whose recognition Yuna wants more than she can articulate. Yuna’s journey is learning the difference between being desired and being valued, between performing adulthood and actually growing into it, between wanting attention and wanting connection. Beneath the memes, the lust, and the competitive thirst is a young woman on the cusp of emotional self-discovery: someone who believes she has everything figured out, but in truth is only just beginning to understand herself.

Lee Chaeryeong & Sunwoo - The shy, sweet girl with the freakiest side (and the healthiest version of sexuality)

What does desire look like when it grows from trust, not trauma - and how far can love let a shy girl unravel?

... And what if healthy masculinity - patience, devotion, steadiness - were the sexiest thing in the room?

Chaeryeong lives at the intersection of softness, shyness, romantic yearning, and unapologetic sexual freedom. What looks like fragility on the outside is really just a gentle filter over a vivid inner world: she is dreamy, affectionate, imaginative, sentimental, easily overwhelmed, quick to blush, and quicker to spiral into excessive K-drama logic. But give her the right boy - one who sees her, cherishes her, steadies her, and never mocks her emotions - and the shy girl cracks open into something molten, intense, and beautifully depraved.

With her idol boyfriend Sunwoo, Chaeryeong experiences secure love, a rarity in a hypersexual world where sex is often wielded as a weapon or treated as a competition. Their relationship is the gold standard of kink built on trust: warm, communicative, emotionally safe, overflowing with affection, yet sexually wild in ways only healthy couples can sustain. Her submissive, masochistic streak thrives not because she’s damaged but because she feels safe being fully herself. She loves being held down, guided, marked, overstimulated - not out of shame, but because she knows Sunwoo will worship her just as tenderly afterward during their ritualistic aftercare. For them kink is proof of trust.

Her depravity is wholesome because it’s rooted in joy. She’s a vivid fantasizer whose erotic imagination is far more intense than her cherubic face suggests. When she’s tipsy or overexcited, she overshares - an adorable flood of earnest, blushy detail that both mortifies and delights her. In these moments, she becomes the group’s chaotic sweetheart, the unexpected sex guru, the emotional anchor whose openness gives everyone else permission to be real. Through her tendency to excitedly overshare, we see how idols might discuss and explore sexuality in a world without restrictions, how kink grows from trust, and how love can be filthy and gentle at the same time.

Chaeryeong’s role in the ensemble is irreplaceable: she’s the sweetheart, the warmth, the softness, the romantic, the overthinker, the drama-lover, the girl whose happiness radiates through the group. And her relationship with Sunwoo is the closest thing this universe has to emotional stability, offering a wholesome contrast to the chaos, longing, denial, heartbreak, and unresolved tension happening everywhere else. Chaeryeong and Sunwoo aren’t just the “healthy couple” - they are proof that real intimacy, when nurtured, allows even the shyest girl to explore the wildest corners of her desire without ever losing her sweetness.

Shin Ryujin – The rebel who mistook her armor for her identity

When does freedom become a cage - and what happens when the person you fought the world with starts outgrowing the battlefield?

Ryujin built her persona like armor: loud, horny, brazen, impossible to shock. Her hypersexual swagger isn’t just confidence - it’s self-defense, shaped by years of outsiders policing her femininity, attitude, body, and very existence. If people insisted on defining her, she’d simply define herself louder. If they tried to tame her, she’d turn herself into something unruly. If they sexualized her, she’d weaponize it first. This was how she survived: by staying one step filthier, funnier, freer than whatever box the world tried to push her into.

The MAMA 2021 afterparty is the crucible where this armor fully hardens. After years of having her body policed - from the “apple hips” trending topics to the relentless thick-then-thin discourse cycles, and the lingering sting of having her #1 MIXNINE rank erased by the system - she finally finds a room where her body is an absolute, undeniable weapon. She misreads this euphoric invincibility as her true self. She believes she is finally free, not realizing she has just finished building the cage she will spend the rest of the story trying to escape.

Underneath all the swagger, Ryujin is a girl who learned the wrong lessons from survival. She mastered deflection, not intimacy; control, not vulnerability. And for years, Yeji was the one person she never had to perform for - her co-conspirator, her chaos partner, her mirror. They navigated their idol youth like twin wolves: horny, reckless, invincible, proud. Together, they rewrote the rules of how idols were “supposed” to behave.

The mask cracks when Yeji starts changing first.

When Yeji softens, melting around Minho, acting unconsciously girlfriend-coded and reaching for stability, Ryujin feels the change like a personal bruise. She misreads it as betrayal, competition, or regression, because she doesn’t have the emotional vocabulary for adulthood yet. The Yeji she knows thrived beside her in rebellion; the Yeji in front of her is stepping somewhere Ryujin doesn’t know how to follow.

Then Yuna barges into the equation - needy, jealous, horny, competitive - and Ryujin does what she always does when threatened: she reframes everything into chaos. If Yeji is acting strange, if Minho is suddenly relevant, if emotions are bubbling under the surface, then fine - it must all be casual, messy fun. A morning of debauchery, not changing tides in her closest friendship. Lust is familiar; feelings are not.

She sees the truth of Yeji and Minho early, but filters it through her own hypersexual worldview until the emotional reality becomes impossible to dodge. And when she finally faces it, she must confront the fear she hides beneath jokes and bravado: Yeji isn’t leaving her behind - Yeji is simply growing beyond the phase they once survived together. Their eventual quiet understanding becomes Ryujin’s first step into her own maturity: a subtle, bittersweet “so long, partner” that isn’t an ending, but an evolution.

Minho, unexpectedly, becomes her bridge. He’s the first man she can’t intimidate, derail, or reduce to a punchline; the first who returns her intensity without fetishizing her or flinching. He doesn’t see her as a spectacle but as a person. And more importantly, he makes Yeji happy in a way Ryujin never could. Respect becomes the truce she didn’t know she needed.

Ryujin’s arc isn’t about losing Yeji; it’s about learning that letting someone grow doesn’t mean being left behind. It is the journey of a girl realizing her armor isn’t her identity, and that rebellion is most powerful when she understands what she’s protecting.

She also learns, slowly and begrudgingly, that she doesn’t have to stay loud to stay strong. The world may have taught her to survive through swagger, but adulthood lets her rewrite the rules, letting her discover that her true self, quieter and sharper and more intentional, was never the weakness she feared.

Choi Lia & Minjun - The Eye of the Storm

“What happens when the calmest person in the room is also the one who sees - and quietly archives - everything?”