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Setting down the advanced homework on Demonic Anatomy that their class had been set a couple of days ago, Sai let out a short breath and stretched her arms, forcing back a groan as multiple bones popped and cracked. Ever since Diavolo informed her that the pass and fail bar for her grades would be the same as the other demon students, Sai had been tutored by Satan most days but today he decided to let her study independently.
“What time is it?...” She wondered as she scanned her bed that was covered in notes and books on the subject she was having to study.
Fishing out her D.D.D from under a piece of paper she gazed down at the screen that told her it was 3:34pm. She had been studying since early morning and had been so engrossed with the texts that she had forgotten to take a break for lunch.
“Crap... That’s another scolding from Lucifer...” Sai swallowed as she become acutely aware of her empty stomach. Carefully manoeuvring around the sea of papers as to not knock any off the bed, Sai hopped off and pocketed her phone, making her way out of her room and down the corridor of the house.
“I really hope Beel left something suitable for me to eat.” She bit her lower lip in anticipation, worried that she may be wrong as she scurried down the stairs and into the kitchen to find Beel stood at one of the marble counters.
He didn’t turn upon her entry, obviously too busy diving into what she could only describe as a rather large cake with a deathly purple aura.
‘Better stay away from that then...’ She thought to herself as she sauntered over to the ginormous fridge that was practically twice her size.
“Afternoon, Beel. Enjoying your snack?” Sai leaned back and peaked her head around the door to see if Beel had heard her this time. He had.
The embodiment of Gluttony twisted his head around to acknowledge Sai after hearing her greeting, silently blinking in surprise with his cheeks full before swallowing hard and wiping the frosting from his face with the back of his hand.
“Afternoon, Sai. You missed lunch.”
The pink haired student grimaced at his obvious words, shrinking a little before hiding behind the door again to rummage through the shelves she had access to.
“Yeaaah... I’ve been doing Mr. Baphomet’s anatomy homework and I guess I got a little too into it and lost track of time. Was Lucifer mad?” She held her breath as she waited for his response, half expecting for the answer to be yes.
“Not really.” The reply was muffled by a mouth full of cake but it was clear enough that she heard. Raising her eyebrows she reached up and grabbed the first thing she saw might have been suitable for human consumption.
“Oh, really?... That’s good then. I don’t feel like having my ear chewed off about skipping meals. This work has already drained me enough...” Once she had secured the box of cupcakes in both hands, Sai stepped away and bumped the door closed with her butt.
“That’s why you need to eat, Sai. If you don’t consume enough nutrients then you won’t have any energy left to-“
‘Trust the Avatar of Gluttony to lecture me about food’ She giggled fondly as she made her way over to the red head, placing a kiss to his cheek tenderly and strategically cleaning off a piece of frosting he missed earlier.
“I know, I know~ It won’t happen again, I promise.”
“Oi oi, I saw that! Ya can’t just go around kissin’ people, Sai.” A new voice had joined them in the kitchen and Sai fought back a smirk as she straightened back up to face the demon.
“I can and I will~”
Mammon sported a mildly annoyed expression on his face at her smug response, crossing his arms and tutting to hide his obvious jealousy.
“Tsk. Whatever.”
“If Levi ever left his room he’d have an absolute meal off of your jealousy, Mammon~” She teased as she plucked a purple cupcake with yellow frosting out of the box and took a bite.
“I ain’t jealous, human!” He baulked, offended that she would even entertain the idea of the great Mammon being jealous of such affection.
‘I mean... I am but there’s no way in Devildom that I’m gonna admit that to her ever...’
Sai just continued to stare at the white haired brother with disbelief, choosing not to pick at his lie and tease him further.
“What was so important that ya had to miss lunch with us? Where were ya?” Mammon asked as nonchalantly as he could, pretending like he wouldn’t care about the answer regardless.
“I was studying for class. You do know what studying is right, Mammon?” She waiting a few seconds before she continued. “It’s when you-“
“I know what studyin’ is!” He growled quietly, grumbling as he walked over to the fridge himself to grab some honey coated bat wings, at which Sai grimaced at.
“Poor bats...” She sulked under her breath before sliding her gaze to his back. He was fully clothed in his normal attire of skinny jeans and aviator jacket but in that moment Sai imagined him in his demon form instead, thinking about his own bat shaped wings.
“Hey Mammy, wanna help me study?”
“As if. Why would I do that?” He scoffed. “A-And what’s with the weird nickname?” He hid his blush behind the door, praying that the cold would cool them down enough for her not to notice.
“I helped you with your Hex and Curses studies; now you can return the favour and help me with my Demonic Anatomy studies!” Her eyes crinkled mischievously as she smirked, blatantly ignoring his other question.
“Just give in, Mammon. Before she uses your pact to get what she wants.” Beel chimed in with the wise suggestion. Sai batted her lashes innocently and smiled brightly.
The light haired demon stared open mouthed at the brother he internally cursed as a traitor to their kind for putting the idea into the woman’s head before stuttering in an incoherent language and giving up.
“Alright fine. I guess the great Mammon can spare a few minutes to lend his knowledge to a clueless human!” He closed the door to the fridge and placed his hands on his hips, puffing out his chest out with pride like a crow trying to impress a mate.
Chuckling at his answer, Sai slid the box containing the rest of the human safe cupcakes in front of Beel as a silent ‘thank you’, giving him a happy smile before sauntering over to Mammon and grabbing his hand.
“Let’s go to your room then!” Sai chirped as she tugged the brother along and out of the kitchen before he could refuse.
The blush came rushing back to his face as he stared down at their linked hands while they walked through the silent hall, taking a moment to overcome the shock before shifting his hand so that their fingers were entwined as she lead him to his room.
This didn’t go unnoticed and Sai found herself blushing too as she forced herself to stay looking ahead, but gently squeezed his hand in response.
Mammon took the lead when they approached his door, his hand hesitating on the door knob for a second longer than normal but went ahead and pushed it wide without any further thought.
As soon as the solid oak doors gave access to Mammon’s private space Sai let go of his hand and bolted to one of the black leather couches situated on the ground floor, skilfully jumping over the back and landing on a cushion with a slight ‘oomf’.
“Careful, you might break somethin’!” The brother scolded, frowning down at the woman as he approached. “And then you’ll have’ta pay for it.”
Sai squirmed a bit to tease Mammon and slid off the cushion.
“I’ll only have to worry about breaking something if you’ve hidden it somewhere where it can easily be broken~ Got anything under...-“ She beginning to lift it up. “- here?!”
Much to her disappointment, the thieving brother hadn’t hid anything under the couch cushion this time and she pouted.
“C’mon, you came to study so let’s get this borin’ stuff outta the way so I can start brainstormin’ ways of makin’ money to place under the cushions in the first place.”
After gathering a pen and paper to take notes, Sai got comfy on the seat and stared up at Mammon expectedly.
“Sooo... what?” He stared back, bewildered as to how he was meant to be helping the human.
“Take your clothes off.”
“HUH?” Mammon exclaimed, taking a step back. “W-WHEN DID YA BECOME SO BOLD!?” His cheeks were practically ablaze and he prayed that they didn’t give him away.
Sai forced herself not to laugh at his outburst of embarrassment and feigned a look of confusion and innocence.
“How am I going to study Demon Anatomy if I can’t see the ‘anatomy’?” She shrugged, purposely dragging her eyes slowly down his body to tease him.
Mammon swallowed hard as he suddenly found his throat drying up, opening and closing his mouth to say something else only for nothing to actually make its way out, lost for words.
Sensing his hesitation Sai let out a kind, reassuring smile and began to shimmy herself off the couch.
“It’s alright, Mammon. I won’t force you. If you’re not comfortable with showing me your demon form I can ask-“
“N-No! Ya asked me first! How could ya even think about goin’ and askin’ someone else to strip down for you?” Mammon panicked slightly and pushed her back down onto the cushion, grumbling that he’d do it for her.
“Just don’t go to any of my brothers for this kinda thing...”
Sai nodded and softened at his words, placing the pen and paper down beside her. Her cheeks flushed a bit as she came up with an idea to help coax the man out of his nerves.
“I promise to make it up to you~”
“Oh yeah? How do ya plan to do that?” Mammon peeked out from the corner of his eye, excited at the possibility of getting paid with Grimm.
“You’ll see.” Sai beamed.
Unable to argue back in fear of driving her off to one of his brother’s rooms for this favour, the second born accepted the unknown offer and stepped back a few further steps as he shrugged his jacket off and effortlessly transformed. Sai watched closely as his tanned skin blossomed the usual white markings across and down his now bare chest. Sturdy black horns grew and twisted from his pale hair like a pair of coiled snakes and his bat-like wings unfurled and drooped from his back.
It was no lie that the natural forms of all the demons she lived with caused a certain fascinated reaction within her. Rivalling the beauty of the angels from the Celestial Realm, they were all so alluring and enchanting in the eyes of humans. Maybe that was the point. Sai thanked whatever fate had lead her to this private moment.
Taking a shaky breath she stood up and steadied herself enough to walk over to the demon that was awkwardly standing in the middle of his room trying not to knock anything over with his wings. He was tense and unsure but nothing in Mammon’s eyes said anything about not trusting the human. They had spent a lot of time together, both on accident and on purpose, so there was no need for that kind of doubt anymore.
“Now for your payment.”
When she was just centimetres away from him Sai lifted up her hands and cupped each side of his face, causing him to widen his eyes and begin to ask what she was doing.
“Wh-“ But he was cut off abruptly when Sai closed the gap and tenderly pressed her lips against his.
Not wanting to keep his hands by his side, Mammon immediately fanned his fingers over Sai’s waist to pull the woman closer, greedy to have her body against his where he insisted she belonged.
Pulling her face away only slightly when she felt the heat from his bare torso against her own chest she whispered lovingly as she gazed into the blues of his eyes.
“Good boy~”
Preening at the praise, Mammon whispered back in a tone so low that had they not been in a silent room, would have most likely not been heard. “More... I’m going to need more...”
‘Greedy~’ Sai smugly thought to herself, happily indulging in Mammon’s demands as she began kissing him once again.
Unbeknownst to the both of them, Mammon’s tricoloured wings tremored with delight as he urged the kiss to deepen by pressing harder, a signal Sai knew to be a request to part her lips. He was cautious about digging his nails into her clothing too much as he tightened his grip, knowing she wouldn’t be too happy about ripping the new anime t-shirt his otaku brother had gifted her last week, even if it were by accident...
Content with Mammon taking the lead with the kiss for now, Sai dragged her hands down from where they were settled on his cheeks to his neck, feeling the taunt and tense muscles in his shoulders relax as she caressed the smooth skin under his studded leather jacket with her palms before finally stopping at his chest.
Satisfied that Mammon was relaxed enough to let her get on with her ‘studying’ without any unease from the demon, she opted to pull away before the lesson turned from anatomy to something even more steamier.
Obviously not agreeing with her action to end the heated make out session, Mammon attempted to chase Sai’s lips only to let out a whine when she denied him.
Stifling an amused chuckle at the surprising sound, the woman lifted one of her hands to lightly ruffle his snowy hair.
“What are you, a puppy?~” Sai teased breathlessly, trying her best to subtly catch her breath.
“S-Stop thaaat...” Mammon grumbled but made no move to stop her from playing with his hair. If anything Sai thought for moments at a time he was actually titling his head so that her hand brushed against one of his horns on purpose.
Testing that theory she grazed her knuckles gingerly at the base of his jet black horns where they started jutting from his skull, searching for signs of discomfort before seeing none and carrying on. Sai examined each of Mammon’s horns, committing to memory the way that the corkscrew structures were just about large enough to fit a finger between the gaps.
‘I wonder if he has ever hidden any Grimm in there...’
Deciding that it would be best to start writing physical notes before she started to forget the details, Sai grabbed Mammon’s wrist and lead him over to the couch where she pushed the glass table in the middle aside out of the way before picking up her pen and paper, resting it against his chest and starting to jot down the specifics she had noticed about his horns.
The demon stayed silent and compliant all throughout the exchange, watching her closely; lost in his own thoughts about the kiss they just shared and hoping to get this studying over and done with so they could get back to it before one of his brothers came to interrupt like always.
The writing stopped and Sai hummed as she pursed her lips in consideration, tilting her head before gazing up at Mammon.
“Do you guys... ever shed your horns?” Sai asked genuinely, looking between them and his eyes.
“Most of us don’t. Levi is the only one who does ‘cause of the way his horns are. They aren’t technically horns ya see. Since horns aren’t actually able to branch out.” Mammon bought his hands up to his own to demonstrate, his claws mimicking branches. “His are more akin to antlers.”
Sai let out a noise in awe at the new information, scrambling to write down the new knowledge with wide eyes and haste as if she feared forgetting it any second.
She continued to ask a variety of questions about his body, none too explicit, while she doodled a sketchy replica of his horns next to the respective notes. One of the notes that Sai made were that the pale markings across Mammon’s chest were considered birthmarks, but were slightly different to the human definition of the same thing.
There was only one thing left to inspect before the study session concluded and Sai couldn’t wait to get her hands on them. Playing off her excitement by biting the inside of her cheek to keep her visibly calm, the student placed the equipment down and slid to her knees, looking up at Mammon with sparkling eyes.
The man instantly misunderstood her motive entirely and started to fluster, stumbling over his words as he tried to back away only to trip back onto the couch that was planted behind him.
“W-W-WHAT ARE YOU D-DOIN’ IN THAT POS- WAH!”
Smacking her hand over her mouth as she snorted, Sai tried not to laugh at the scene but it was too hard not to.
“D-DON’T LAUGH!” Mammon scolded Sai as tears formed in her eyes from the out burst of laughter.
“S-Sorry, sorry.” She wiped them away and took a few deep breaths before crawling over to where he was sat.
“I wanted to look at your wings, if that’s alright with you?”
“S-So that’s what ya were plannin’... ya could have just said so. Nearly gave me a heart attack gettin’ on ya knees all of a sudden...”
Sai just nodded and looked at him expectedly, waiting for permission first before touching anything.
Mammon looked at her for a moment before averting his gaze, seemingly remembering something and squirming uncomfortably.
“M-Maybe it’s not a good idea to touch ‘em.”
Sai deflated a bit after hearing his words, feeling a little disappointed.
“Aww, why not?” She pouted, deciding that she wouldn’t push him to do something he didn’t want to do but was curious as to why she wasn’t allowed.
“No human has ever touched ‘em before.”
“Do you think I will die?” Sai’s gaze wondered down to his wings where they were crumpled between his body and the couch cushion.
“What? No! I don’t think so at least...”
“Then why are you concerned about me touching them?”
“‘Cause they’re-“ The rest of his words we’re muffled as he lowered his voice in embarrassment and covered his mouth with the back of his hand, still refusing to look at the human who was ignorant to the circumstances at his feet.
Silence spread throughout the room as Sai strained to hear what Mammon was saying, titling her head and frowning a little.
“What was that, Mammon? I couldn’t quite hear that last part.”
Mammon opened his mouth to say it again, pausing for a moment before removing his hand to reveal his rather flushed face, much to Sai’s amusement.
“‘Cause they’re sensitive...!”
“Ohhhh...” Sai hummed in realisation before squinting her eyes playfully. “Aww!”
“It’s nothin’ to ‘awww’ about! I’m serious.” Mammon huffed and pouted, crossing his arms in front of his chest like a cranky child.
“Alright, alright~ Can I at least see them closely so I can make notes? I won’t touch them then.”
“You can touch them, just... don’t go tuggin’ and pullin’ on them, that’s all.” He looked down at Sai nervously, starting to get worked up again.
Not wanting to make him feel uncomfortable again, the woman placed a hand on his knee and squeezed gently, a sign to reassure that he can trust her with this.
“I’ll be gentle, Mammon. I promise.” She crooned and gave him an affectionate look before shuffling back to create a space for him to kneel. “If you tell me to stop then I will.”
Nodding sheepishly and deciding to take her word on her promise, Mammon slid off the couch and knelt with his back facing her so she had better access to his wings, his fists balling up on his lap as he prepared himself.
Sai gently pressed her fingers against the back of his jacket, slowly lowering them as to let Mammon get used to her touch first, watching as his wings twitch nervously with the initial contact.
“I’m going to touch them now.” She announced as her fingers drew closer, the pads making contact with the curved juncture where the lower half of his shoulder blade met his wing.
“Go ahead.”
With his permission Sai started to glide her hands down the length of the muscle that connected them to his back, noting the texture and size diligently. What also didn’t go unnoticed was Mammon’s breath hitching every so often as he struggled not to squirm.
‘He did say they were sensitive... is he in pain?’ Sai frowned behind him, wondering if she should stop before another possibility popped into her head. ‘Or... perhaps it feels good?’
Observing his reaction as she stroked the area tenderly, the student slowly leant down to press a kiss to the firm muscle, earning her a jolted gasp from the demon as the rest of his wing flared out in surprise, peeking over his shoulder to fix Sai with a look.
“Oi oi.. now why’d ya do that...”
Sai pulled away and giggled, pressing another kiss to his hair as the man pouted slightly at the treatment.
“Because I felt like it~ I was just making sure you weren’t lying to me.”
Mammon sighed and faced back ahead, signalling that she could carry on examining.
Utilising the fact that the action had caused Mammon to outstretch his wing, Sai carried on moving her hands along, humming in awe when the feeling morphed from fuzzy and firm to leathery and delicate. Just to confirm that she wasn’t imagine it, she returned to the previous spot, alternating back and forth between the areas until Mammon let out a frustrated groan.
“Will ya stop that! Are ya doin’ it on purpose now, teasin’ me like this?”
“Sorry, sorry! It’s... surprisingly soft compared to the rest of your wing.” She commented as she gently pinched the leathery webbing between the boney fingers. “And this part feels like it could tear at any moment...”
Mammon huffed. “It ain’t that weak.” He lifted the wing up a little so that the light from the ceiling illuminated through the thin material. “Yeah it looks as thin as Grimm notes but it’s quite sturdy!”
“Ohh I see, I see!”
Sai let go and proceeded to look over the rest of the wing, pausing for moments at a time to write down what she had learnt from this session so far, including the flustered reactions from the subject himself.
Over the space of an hour and a half Sai had learnt so much about a demon’s anatomy, including that all demons, or at least the seven brothers, all have a weak spot that is more sensitive to touch than the rest of their features in this form; much to Mammon’s distress at accidentally revealing the information that the smug woman was sure to take advantage of sooner or later.
“Alright! I’m done now.” Sai gathered up her notes in a neat pile and started to get ready to leave Mammon alone after taking up so much of his afternoon.
“Ya leaving?”
“Mmhm, I think I’ve got enough notes to grasp the basics! The rest should be fairly easy now I know a bit more.”
“Oh...” Mammon didn’t turn around to face Sai as he spoke, causing her to fret that she had done something wrong.
“W-Was there something else?” Anxiety pooled in her stomach as she froze still, her mind racing to overthink about how maybe she had been hurting him all along and he had been too afraid to say anything.
Mammon didn’t say anything for a few seconds but to Sai it felt like hours. She started to internally panic as her eyes started to burn, threatening to form tears as she opened her mouth to apologise for causing him pain; all trace of the happy atmosphere they had created disappeared.
It came as a shock to her when his demon form phased away and he twisted around, surging forward and knocking her onto her back as he loomed over her body. It took Sai more than a second to realise that Mammon’s face was as red as a tomato and the poor demon was panting. Her eyes widened and her mouth hung agape as she recognised the hungry look in his eyes. She wasn’t so upset at the idea that she had hurt him anymore, but instead the buzz of desirable tension clung to the limited space between them.
“I was wonderin’... if we could carry on what you started earlier...?” Mammon purred as he inched his face a little closer.
Without any hesitation, Sai lifted a hand to the back of Mammon’s head to pull their lips together, wasting no time in accepting the offer.
For the second time that day, Sai ended up missing yet another meal time in the House of Lamination.
Oh well.