Work Header

Ryuuji’s Advance Guide to Demonic Relationships

Chapter Text

As you grow with your demonic partner, it is inevitable that you will find yourself around them in varying weakened states. Whether it’s when you’re sleeping and suffer a nightmare, whether it’s when you’re fighting an illness, whether it’s when you’re exhausted for some reason or another, or something else entirely, you will find yourself around them in a vulnerable state.

First, beware. If there is a reason you’re in that weakened state and that reason happens to be human or demon, your demonic partner is going to go after it. Keep your tongue if it’s not someone you want hurt or potentially enhilated. 

Second, just let them help you. They’ll get more and more aggressive in their insistence until you do. Just accept the help and move on with your life. It’s one of their prime ways of showing love. Demons tend to plow over anything they see as weak, so your demonic partner trying to help you and carry you on is their way of providing and showing they love you. They’re not letting you get left behind. They’re defending you when you can’t and making sure nothing else knows you need help so you’re not seen as weak.

Third, take care of yourself. It saves everyone a lot of stress and hassle if you just don’t get sick because you weren’t taking proper care of yourself. 

Lastly, it can be scary to be in a vulnerable state like that. It can be frightening with anyone, but with your demonic partner, it can feel like a big and dangerous risk. Depending on your relationship, it might be. I was lucky with my partner in that I already had a strong relationship with him before we got together. I already trusted him with my life, and I’ve been fortunate in never misplacing that trust with him. If you’re nervous about trusting yourself to your own partner, take things slow. Build the trust slowly, and talk with your partner.

Also, get ready to be scented a lot. Worried demons are scenty demons. It solves absolutely nothing, but that will not stop them from trying, darn it.

Bon pressed his head against the door frame and exhaled wearily. The damn key was somewhere in his bag, and finding it in those depths seemed like an utterly insurmountable task. 

He was so tired.

His vision was a bit blurry with the heavy exhaustion. It was causing the world around him to seem a bit unreal. Too distant to be truly concrete. This was his final week of this assignment, and he’d finish his finals at college (at least for this semester) and if he could just hold out a little longer, he could rest.

But first, he had to find that key. Just… just another moment of rest. He could find it in a moment. He could find it, open this damned door, and drag his feet far enough inside to find the couch. He could do it. Just another minute. He thumped his head against the door, wishing it would open, and nearly jumped when the lock clicked from inside and the door opened. He hadn’t had time to support his own weight, and went crashing forward.

Right into Rin’s warm arms. “Ooph!”

“Rin?” He slurred, trying to catch himself and struggling against the blanketing exhaustion. 

“Ryuuji!” Rin tugged him into the room effortlessly. He flicked the door shut again with his tail, tripping the lock and shifting Bon around to an easier to handle position with a kiss to his temple. 

“I’m so tired.”

“Course ya are! You’ve slept like two hours a night for the last week.” A less sleepy Bon would have noticed the worry in Rin’s voice, but just understanding the words was taking a lot of effort. He was only upright because Rin was holding him.


He grunted a response and shifted his head up. It pulled at the bandages on his neck, and he couldn’t help but grunt again. (This time in pain.)

The change was almost instantaneous. Rin’s hair lit with bright fire, his jaw widened, his teeth grew, his ears lengthened, and the blue flames burned over the rest of his body as Fireball forcibly took over with a growl.

“Sexy’s hurt?!”

He was so damn bright and Bon was so damn tired. “Not now,” he grumbled, closing his eyes against the light as he was manhandled towards the couch. “Just a few cuts. Nothin’ serious. Need a shower. Got some… some work…” 

Rin ignored him and set him on the couch. His hands cupped Bon’s cheeks to tilt his head up so Rin could stare worriedly into his eyes. The flames were far too bright, but Bon could see Rin’s fire-twisted eyes and red pupils. Fireball was still in charge. At least he wasn’t being loud now. 

“Sexy?” Rin’s fingers trailed down to his throat, brushing along the edge of the bandage Lewin had sloppily applied. “Who did this?”

“Couple of demons. We got ‘em.” He slouched back into the couch with a world weary sigh that had Rin growling lowly. Bon closed his eyes and gave his head a small shake. “Don’t get mad. It’s not a big deal.”

“Sexy hurt,” Rin growled back, and he didn’t need the rest of the words to know that Rin meant it wasn’t okay. As long as he was being quiet, Bon could deal with the growls. 

“Not bad,” he promised, yawning and trying to keep his eyes open. It had been ages since he felt this tired. It was a horrible physical sort of weight. His body was uncomfortable and heavy and stiff, and there was a cottony feeling in his head. His sinuses even hurt. Just thinking felt like a monumental effort.

The fingers dragging roughly through his hair gentled their motions and shifted to rub tension out of his temples. He groaned in immediate appreciation and melted into the couch. If he opened his eyes, he had no doubt that the human part of Rin was back in charge. 

“Thank you,” he slurred. 

Rin’s lips pressed against the pained furrow in his brow. He smoothed his expression and let the gentle affection and heat seep into his skin.

“I’m going to try and hold him back, but you should know that you smell a lot like Karura.”

Bon grunted in displeasure. “Shit. Is it on the couch?” How had he forgotten to shower before he came home?

“Yeah.” Rin pressed another kiss to his forehead, “but I’ll burn that scent out later.” His nose brushed through Bon’s hair, gently scenting him to dampen down the other demon’s scent. 

“No,” he whined (and would never admit it) “Fireball will really burn it. Let me just… just get the, uh,” Mara’s menace, his brain would not make words. “Clean stuff.” The demon scent bottle. Shiemi had made it for them. What did he call it? 

It didn’t matter. He didn’t need its name. He just needed help getting up. “Come on, help me up?” He reached for his boyfriend’s shoulder and missed a bit, hitting him in the chest instead. Not hard enough to hurt at all. He apologized anyway.

Rin caught that hand and pressed a kiss to it. The sweet action had Bon’s eyes tearing up a little, and shit, he needed some sleep. 

“I don’t know what you’re thinking,” Rin said as he simply lifted Bon up and off the couch, “but you’re not doing any more work tonight. You’re gonna wash, and then you’re gonna nap while I whip you up some food.”

“I got more work.”

“And I will bite Lewin if he even tries to contact you. You are taking a damn nap.” Rin nuzzled his cheek in another scenting and carried him towards the bedroom and bathroom. “Shower or bath? Which do ya want?”

“Shower. I don’t have—” he yawned dramatically and realized Rin was carrying him for the first time. “— time for a bath.” Rin nuzzled him for a moment longer and kept carrying him to the bedroom. 

“Fine with me. The quicker you’re clean the quicker you can nap.” 

Rin set him down on the bed and bent down to take his shoes off. How had he forgotten to take them off when he’d come inside? 

“Can’t nap. Gotta study.” He had to graduate. They couldn’t afford him to take another semester. The classes weren’t hard, but he’d hardly had any time to invest in them.

Rin slipped his socks off and set them to the side. He sat up, reaching for Bon’s shirt before seeming to think better of it. He sat back on his haunches and lifted Bon’s left foot up, working his thumbs into the arch and forcing out the tension.

Bon promptly flopped back on the bed (he’d have to remember to spray this as well) and moaned. 

“You,” Rin drawled, running his fingers along Bon’s heel and releasing knots he hadn’t even been aware of, “are going to nap, babe.”

“No,” he grumbled, closing his eyes and trying to tell himself to pull his foot free and stop melting into this bed.

Rin’s hands heated up as he worked the tension out. “Yeah ya are. I’m gonna make you salad and curry for dinner. You’re gonna shower, nap, eat, and then take a long bath. If you skip out on any of those, I’m letting Fireball loose to do whatever he wants.”

“I’m not scared of him.” 

Rin dropped his foot (tragic) and crawled up the bed (not tragic) so he was hovering over Bon. His eyes were flickering with fire and there was a mischievous sort of promise in that gaze. 

“You should be. He’s furious with you.” 

Bon frowned. Even past the heavy exhaustion, he knew he didn’t want that. “Why?” Had he hurt his boyfriend somehow?

Rin kissed him instead of answering and started to work the buttons on Bon’s shirt loose. His warm hands slipped inside the now open shirt, sliding Bon’s under shirt up and teasing at his skin. 

“You know how jealous we get,” Rin mumbled between kisses as he worked at Bon’s belt. He should move and help in some way, but it felt impossible. Each of his limbs had to weigh a few thousand pounds. Just kissing Rin back in this sloppy way felt like it was taking most of his concentration. “You coming home smelling like other demons, spending all your time studying, passing out and then forcing yourself to work harder…” Rin sat back and hauled Bon upright as he did. This would be incredibly hot if he wasn’t so damned tired. Karura just had to feed on his actual life force to stay around. If he didn’t have to summon, he’d just be a normal tired and he could take proper advantage of his sinfully hot boyfriend perched on his lap. 

“He’s gonna be handsy.” Rin tugged his own shirt off and tossed it aside. His tail lifted up with the motion, flicking through the air as he pulled Bon’s shirts off and tossed them to the floor. Bon would have to clean that up. Were there other clothes? When was the last time he’d—

Rin kissed him again, hard, and bit his lip. Bon gasped at the sting and clutched Rin’s hips. The warm heat of Rin’s skin felt wonderful against his own bare chest. Another kiss, and Rin let him go. He fell backwards, entirely taken off guard by just how much his boyfriend had been holding him up. Rin climbed off the bed and tugged Bon’s pants off. Those were also tossed to the floor. Rin once again scooped him up and carried him into the bathroom.

“Don’t fight me on this,” he quietly ordered as he turned on the shower. He propped Bon against the wall — which was a bit insulting because Bon was totally capable of standing on his own, he was just choosing to stay propped against this wall — and messed with the spray. He turned it on, Bon tensed in anticipation of cold water, and Rin’s body lit with bright flames before the water could hit him. The flames heated the water up and filled the small shower with steam. Rin ditched his pants and underwear as he worked, and sidled up in front of Bon with a determined expression. 

“I’ll take a nap, but I’m going to do a few hours of studying tonight. I got another mission with Lightning tomorrow and—”

Whatever control Rin had audibly snapped. Rin ignited with intensely warm and bright flames. He surged forward, crowding Bon against the wall and not giving him an option to escape. Clawed fingers shot out to press against the tile on either side of his head, cracking them and that was something else he’d have to—

“Sleep!” Fireball snarled, showing his teeth in blatant threat. They were the length they only got when they were in a fierce fight. Deadly. It should be entirely ridiculous, and might just be the silliest thing Rin had ever pulled that look on, but Bon was too sleepy to recognize the hilarity of the situation. He cringed back from the heat, wincing when it caused him to pull on some of his bandages, and a twist of fear went through his gut.

Rin cringed back like a kicked puppy. Bon blinked, realized what had happened, and reached for his retreating demon. Rin could smell when he was afraid, and it never failed to break Fireball’s heart when he scared Bon. It was unavoidable sometimes, but that was usually only when Rin went a bit feral. 

“Hey, no. Don’t—” he slipped, clumsy in his exhaustion and would have fallen if Rin didn’t catch him. Bon took advantage of that moment and wrapped him up. Rin could take his weight. 

Sucking in a breath, he leaned on Rin’s shoulder. “Don’t go.” There were flames still pouring off Rin, evaporating all the water before it could hit him. The steam felt nice, but he wanted to wash up. Swallowing his pride, he closed his eyes and accepted the truth. “I need help.” He was too tired to manage this properly, and if Rin left because he felt guilty, Bon would absolutely slip in here and hurt himself.

Rin propped him back up against the wall. Fireball was still in charge, and it was obvious even with Bon’s unfocused vision that his lover was incensed. 

Rin’s hands came back to him once they were coated in far too much shampoo. They tangled in Bon’s hair, rougher than Rin would be, but still gentle for Fireball. He was muttering something as he worked up a ridiculous lather in Bon’s hair, scrubbing away the dirt and blood there with a vengeance while he grumbled out a stream of angry Gehennan. Thankfully they used the unscented stuff, or Bon would reek. 

“Hey,” Bon slurred, feeling heavy and like his head was full of something rougher than cotton. “Don’t be angry.”

“Sexy hurt,” Rin growled. He rinsed his hands off and pulled Bon to stand under the spray. He closed his eyes to keep the suds out, and Rin’s fingers pulled roughly at his hair, the anger making his movements sharp. Bon winced, and Rin’s hand withdrew. He growled again. “I wanna kill.”

Bon dragged his hands over his eyes to clear away the suds and water. “No.”

Rin was flickering with barely concealed fury. He had the conditioner in his hand and the top looked like it was about to pop off. Bon reached for the clenched hand and soothed his fingers along the back of it. 

“Calm down, Fireball. I’m fine. I already told you we got the demons.” 

Rin shook his head. “Lightning hurt Sexy. Karura hurt Sexy.”

“They didn’t.” Bon cupped Rin’s cheek and pulled him into a quick kiss that tasted like soap. “It’s just part of the job.” 

The conditioner was worked through his hair. Rin pushed him back against the chilly wall and brought the loofa up. His claws tore at the netted fabric, but he was fairly gentle as he scrubbed it over Bon’s body, pausing over each bruise and cut and scowling all the more. 

He was pulled back under the water, manhandled into a clean state, and pulled out of the shower. Rin didn’t give him a chance to bother with any towels before he ignited and evaporated all the water off Bon, showing a remarkable level of control of his flames. They were nothing but a warm and gentle caress against his skin.

He was then carried back to bed and dropped on top of it, still entirely naked, and tucked in. Rin wrapped him up in the blankets like a burrito so he couldn’t move any of his limbs. His brain felt like sludge, but that wasn’t going to stand.


Rin paused mid rise and frowned at him. At least Fireball could hear the worry in his voice even if he didn’t get the reason. 

“Loosen me up. I don’t like—” he swallowed, heart starting to beat a bit faster as Rin shifted away. “I don’t like being restrained like this.” He hated it. He’d been tied up and held down on too many fights gone wrong to be comfortable in this position. His muddled mind couldn’t separate those dangers from the now.

Rin just stared at him. Fireball wouldn’t leave him like this, would he? Rin wouldn’t, but Fireball was often a wildcard. 

Bon tried to shift himself and couldn’t. His breath quickened, and it didn’t feel like he could get any real air. The fright of being left and trapped to suffocate was getting bigger.

Fireball bared his teeth and sprang at Bon. He tore through the blankets — one of Rin’s fuzzy ones, his boyfriend would be pissed at that later — and hugged Bon to his chest. Bon clung to him, too worn out to make sense of his own fright and just happy to be free. Rin’s cheek rubbed against him in quick sharp movements, frantically scenting Bon.

Kuro yowled from the hall and Rin promptly snarled at him. 

“No,” Bon grumbled into Rin’s shoulder. “It’s just Kuro.” 

Rin’s nose dragged along his now damp bandage. He’d have to change that later. There was so damn much he still had to do. 

“Light,” He growled. 

“Helped,” Bon answered. “Don’t dare hurt him.” Lightning would be confused, and then he would lay Rin flat on his ass. 

With obvious effort, Rin took control back. “Just rest, babe.” His hands were tight on Bon’s elbow as he lowered him back on the bed. “I’ll,” his features shifted a bit, but he got control back, “keep him here. Sleep while I get your… dinner.” Rin kissed his cheek twice, trying to subtly scent him, and pulled away. Bon watched him go, a bit dizzy with the exhaustion, and stared at the remains of the blanket. He managed to roll over and find his pajama pants. He pulled those on, draped part of the remainder of the blanket over his shoulder, and told himself he’d just lay here for a few minutes while he sorted through his to do list.

He passed out after all of a minute.

Something smelled fantastic, and Bon was surrounded by wonderful warmth. He pried his somehow heavier eyes open, and blinked to find himself looking at the kitchen. Or into the kitchen. He was laying on a cushion at their kotatsu. Kuro was purring near his head, and Rin was finishing up the food.

“Sexy stay still!” Rin snapped, sending a sharp look his way. Fireball must have moved him here. 

"I didn't move." He yawned into the pillow and tried to tell himself to sit up. He should at least be reading. 

Rin put his spoon down and stomped across the room. He was covered in flames. Bon had really pissed him off. "Sexy stay." Rin ordered again. He dropped into a crouch in front of Bon, white tail flicking through the air in agitation and leaving a trail of flames as he stared down at Bon. "I keep safe."

Had Bon been in a clearer headspace, he would have given up. Rin was worried, and he didn't like purposefully upsetting him. He could just get up earlier — because the boy he loved would never get up early — and he'd do any pressing work then. He'd spend the night curled up at the kotatsu where Rin could keep an eye on him — because he knew that was why Fireball had dragged him here. He was worried — and he would enjoy a good meal and heal.

But Bon was exhausted and he always got stubborn when he was exhausted. 

"Get me my book, Fireball. I already—"

Bon was sort of upright one moment, and down on his back with a furious halfling sitting on his chest the next moment. His hands were pinned over his head, and Rin was once again garbling in Gehennan. The harsh syllables sounded especially angry today. He recognized a few of the sounds —stop, hurt, and need — but it didn't make enough sense to pull a meaning out. Just that his boyfriend was angry, and Bon was too tired to properly fight him. 

Kuro meowed and Rin's head snapped towards the stove. Before Bon could make sense of that, Rin had him standing and pinned against Rin's side. He was dragged into the kitchen where Rin pulled their dinner off the stove and set it over to cool. Bon continued to be hugged to Rin's side and dragged around the kitchen until Rin had plated everything up. He was then dragged back to the table, tucked in, and given a plate of food. Rin sat right next to him, and tried to feed him the curry like he couldn't manage it on his own.

That got Bon's brain going enough to push his boyfriend (gently) away, kiss his cheek, thank him for the meal, and accept that his plans were not happening tonight. If he pushed anymore, Fireball was going to get pissed. If he fought him on this, he'd end up wrapped too tightly again and Rin would probably get his ass kicked by Lightning for trying to start a shit. At least he couldn't get at Karura unless Bon or Tatsuma summoned him.

Savoring a bite of curry, Bon leaned against Rin's shoulder, enjoyed the gentle heat of the kotatsu, and tried to ignore the ache in his head. He'd take the ordered nap and just work harder tomorrow. It'd be fine.