Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/4149573.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M
  Fandom:
      カーストヘヴン_|_Caste_Heaven
  Relationship:
      Kuze_Natsuki/Kusakabe_Atsumu
  Character:
      Kuze_Natsuki, Kusakabe_Atsumu, Kuze_(Caste_Heaven), Kusakabe_(Caste
      Heaven)
  Additional Tags:
      Established_Sexual_Relationship, Explicit_Sexual_Content, Rimming, Come
      as_Lube, Oral_Sex, Blow_Jobs, Anal_Sex, Multiple_Orgasms
  Stats:
      Published: 2015-06-17 Words: 1643
****** Helm's Deep ******
by RubyFiamma
Summary
     Kusakabe just wants the entire world at his fingertips but his
     universe only stretches as far as Kuze.
                                  Helm's Deep
===============================================================================
 
 
The examination room table is cold against Atsumu’s skin. The chill that seeps
through his skin and settles into his blood makes it harder for him to breathe;
though the gusts of air that he chokes on are likely to do with the heat of
Kuze’s mouth pressing tender kisses against his stomach and the slide of the
other’s soft fingertips along the insides of his thighs.
There was a time where Kusakabe trembled in fear instead of pleasure; a time
when jeering voices over his shoulder made him quiver and now it’s the liquid
silk of Kuze’s voice calling out his name, “Atsumu…Atsumu.”
There was a time where Atsumu was nothing but trash hiding behind a fortress
long since crumbled, once kept strong and solid by his destitute and social
standing but Atsumu is stronger now; he’s got powernow and it comes in the form
of Kuze’s lips rolling over his flushed length, sparking electricity through
his veins and Atsumu feels like he can bring down an entire army on the
strength borrowed from another.
“Kuze.” His name is easy on Atsumu’s tongue, and he can’t help but hiss from
the almost-too-painful heat that sears his skin like sunburn. “Kuze… More,
Kuze. More.”
His touch is addictive in every sense and Atsumu doesn’t know how to be himself
anymore, doesn’t want to be himself – his old self, the piece of garbage that
was tossed aside and stepped on; kicked down and beat on and it’s like he’s
melded into Kuze, like every inch of Atsumu’s existence belongs to him.
“Mmh, Kuze –- I -– Kuze, I’m gonna--”
He feels drunk. He doesn’t know what drunk feels like, but he suspects it must
be something like this. Shaking and shuddering as Kuze’s mouth milks him
through the orgasm that draws tight in his belly and surges lighting-quick
through his blood. It breaks the surface of Atsumu’s defenses and drags him
under, like he’s drowning as he gets swept away by the current. He can’t
breathe; his chest aches with this pressure that feels like it’s crushing him
and the tears are back, streaming grit and salt down his face.
Atsumu hasn’t even come up for air yet when he feels Kuze pull apart his fleshy
mounds, legs splayed out like he’s lost all control of his limbs and they’re
being held up by marionette strings. Kuze spits then, Atsumu can feel the hot
spill of come and saliva spurt slick against his entrance and the sheer
knowledge of his own come being used as lubricant is enough to fill Atsumu’s
cock half-hard.
“You taste good,” Kuze purrs, his breath splashing cool against Atsumu’s heated
skin.
He tries to breathe Kuze’s name but it comes out in a groan and he jolts when
the other licks over his entrance, makes him whine desperate for more. Atsumu’s
certain the other knows his body well by now, knows that the quiver in his
thighs is a plea for Kuze to keep the warm swell of his tongue sweeping over
his entrance like he would an ice pop in the summer heat. Atsumu knows it’s
dirty, knows that whatever this is must make him some sort of bad boy but he
can’t stop the reckless ecstasy that thrums in his veins and sparks his blood
aflame.
Kuze makes him feel wonderful, love-drunk with whispered words rich and cloy
and Atsumu knows he should keep his distance, retreat to the sanction of the
mountains that have not done well to shelter him in the past. The keep is where
he stays, where his mind goes when he’s being tortured by cruel life itself and
when he feared he’d never be free, Kuze rescues him from peril like Atsumu’s
own white knight in shining armour.
There are slender fingers inside him now, crooking and curving alongside Kuze’s
tongue and it’s too much all at once, the crushing pressure in his chest and
skin so hot that he’s burning from the inside out, Atsumu’s afraid he’s going
to combust into flames right here in the infirmary. He’s panting hard, breath
too thin and shallow like he’s too high up an altitude. It makes sense, Kuze
takes him to a whole other  plane.
“Mm,” he hears Kuze hum from above him, when his fingers have stilled and
Atsumu has had time to sort through the pieces of the other’s speech. “You’re
so cute, Atsumu.”
Atsumu props himself on an elbow, glances up at Kuze through bleary eyes and
even without his glasses, Kuze is the most gorgeous thing he’s ever seen. With
the sun filtering in through the blinds over the windows, orbs of light adorn
his skin like crystal pearls and shadows fall through the strands of his
coffee-rich hair.
“Don’t make fun of me,” he mumbles, his mouth dropping into the shape of a
pout.
“Ah, Atsumu… I wouldn’t dream of it.”
When Atsumu meets the other’s eyes, they’re soft and warm, like glowing embers
of a slow burning fire. Kuze smiles as he brings the condom foil up to his lips
and tears through the wrapper with his teeth, and Atsumu can’t help but think
the other’s look is like a siren’s song luring him out of his shell and into
unknown depths but he’s not afraid. Kuze makes him feel safe, makes him feel
wantedand for that Atsumu is ready to tear down any barriers that get in his
way.
“I’m going in,” Kuze croons, gentle but seductive, a tone that winds like a
coil up Atsumu’s spine and flushes heat into his limbs.
“Hurry,” Atsumu whines, clawing at the fabric of Kuze’s shirt to draw the other
in closer. The wait has long since been unbearable, the ache in his joints for
Kuze’s skin to touch his own is unfathomable.
“Haha,” Kuze laughs, bright bursting sound that spills from his lips like a
bubbling brook. “Such an eager little rabbit.”
Atsumu makes a sound, like a purr of satisfaction and a frenzied supplication
before Kuze grips his hip and enters him slow like Atsumu were made of glass
and anything harsher would shatter him. It doesn’t matter, the burning pressure
of being stretched open languidly is something Atsumu’s come to relish in but
his entrance is slick with come and spit so it makes the motion simple, if not
easy.
Kuze groans, Atsumu watches as his lashes flutter and sweep across his cheeks
before throwing back his head and rolling his hips into the first grind. Eager
is right, he supposes and when Kuze leans in against his thighs and starts to
thrust, Atsumu is already reaching for the crisp white of the other’s shirt so
that he can tip his head up and press his mouth against Kuze’s lips, despite
the undesirable pull in his thighs. They’re hot to the touch, Atsumu can almost
feel his lips burning from the sparks of friction against his mouth.
“Feels good,” he murmurs on borrowed breath. “Deeper, Kuze.”
There’s a laugh that ruffles his hair, and pressure spiking at his spine as
Kuze pushes deeper and Atsumu can feel the other’s cock sinking further into
him with each rock forward. Kuze hooks Atsumu’s legs over his shoulders until
he’s driving harder and harder and Atsumu can’t keep his grip. He falls back
against the table, warmed with the heat and slick with the sweat of his body,
and lets Kuze fuck him until the only thing he can see is white across his
blurred vision. There are tears streaming down his cheeks from pain and
pleasure alike and compression ballooning against his ribs. He can’t breathe
again, and sound is vibrating in his throat without a conscious effort.
Kuze draws back and snaps his hips, and something visceral erupts from Atsumu’s
mouth. “There,” he purrs. “That’s the place Atsumu feels good most, isn’t it?”
He can only nod, short bobs of his head as he writhes underneath Kuze, and
before he can blink away his tears, Atsumu’s shuddering through waves of
euphoria that leave him weightless, suspended in animation with no concept of
time or space. The last thing he feels is heat, spurting across his chest and
spilling down the crease of his ass, warm like Kuze’s touch across his skin.  
He’s not sure how long he’s out for, but when he comes to, it’s to the gentle
tapping of Kuze’s hand at his cheek and the coaxing melody of Kuze calling his
name. The world around him is hazy, blurred edges of nothing but white and his
entire body is empty but weighted with sated pleasure.
“Ku… Kuze?”
“I’m here,” the other whispers and Atsumu can hear the smile in his voice. “You
passed out for a little while. Looks like I have to be more gentle next time.”
“N-no,” Atsumu stutters, dragging himself up on the table with strength as thin
as thread. “No, I want…” He can’t finish his sentence for the emotion rushing
in and swimming through his thoughts. There’s not a thing he wouldn’t do for
Kuze, not a single particle of himself he wouldn’t offer to the other. He wants
for Kuze to see only him, no Queens or preps or other interferences that will
drive Atsumu into a frenzy, wild with lust-filled jealousy and rage. He doesn’t
want it to be that hard, he doesn’t want to have to share Kuze with anyone, or
anything.
“What is it that you want, my Jack?” Kuze asks, spreading kisses along the
expanse of his collarbone. He can smell the sun in Kuze’s hair, feel the ends
sweep against his skin like feathers of a dove.
“I want… I want to be your King,” Atsumu answers with a smile, tucking a lock
of satin strands behind Kuze’s ear. “I want to be at the very helm of this
caste heaven.”
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