AN: Terms used that you might not be familiar with:
Shadowhunter/nephilim - are a secretive race of beings who are humans born with angel blood. Their mandate is to keep the peace in the Shadow World and keep it hidden from the mundane (human) world while protecting the inhabitants of both worlds.

Shadow world - term generally used to refer to the hidden, supernatural part of the world that Shadowhunters and Downworlders share and is also being aded by demons.

Parabatai - a pair of Nephilim warriors who fight together as lifelong partners, bound together by oath, regardless of their gender.

Runes/marks - symbols that grant beings various supernatural abilities. 

Stele - tool used by Shadowhunters to draw runes onto their skin.

Witchlight - a light, flat, smooth gray stone that emits light, giving off a pure white glow when held by Shadowhunters.

WARNING: Fast paced lame story ahead. I'm sorry I tried TT TT

The moment they entered the abandoned building, a strong distinct scent of death welcomed the two Nephilim. They've been watching over the establishment for a week now keeping an eye out on a demon, a shapeshifter, that has been causing ruckus to the area.

Taeyong signaled Jaehyun to go the other way and the younger nods his head following the elder's order. Five years of being parabatai have made them develop a setup where Taeyong, being the older and smarter one, leads their operation while Jaehyun mostly do the killings. The two Shadowhunters took their separate paths silently, not wanting to alert the demon of their presence.

It was dark and the air filled with dust. Jaehyun fished his witchlight out from his pocket and watched it glow before continuing. It seems like the building was abandoned before its construction can be finished. The floor they're in was wide and empty with bare walls and a few pillars at the middle. Cautious steps were taken, checking every corner for a sign of the demon being there. Jaehyun then feels something, someone looming from behind.

The young Nephilim turns around, one hand holding the witchlight while the other clutching his blade, only to find Taeyong standing before him.

"Jesus hyung you startled me," Jaehyun muttered. Taeyong just stood there as if he was a mannequin, not moving an inch nor showing any expression on his face. There was something off about the older that Jaehyun can't point his finger on. "Hyung is everything alright?" he asked, walking closer to him.

Jaehyun keeps his blade back and reached his hand forward to touch Taeyong but before he could, Taeyong's eyes rolled back and bared his sharp teeth. Demon. Jaehyun reacted a second late, by the time he thought of attacking the shapeshifter, he was already bitten on the arm and lets out a yelp.

Taeyong sprints the other way as soon as he heard Jaehyun's cry of pain. Despite being one of the strongest Shadowhunters, the younger can be a bit careless sometimes causing him to be in danger. When he finally reaches Jaehyun, he can see the younger struggling on defending himself. Immediately he takes an arrow and aims at the monstrous demon hitting it near its right shoulder. It burned the part but it healed in an instant. The demon turned its back on Jaehyun and walked towards Taeyong's way, searching where the arrow came from. Just by looking at it Taeyong can already tell the demon is blind and is only relying on its nose. He continued shooting arrows at the demon, burning holes into its body, while running away from it. Jaehyun scampers back on his feet and takes out his seraph blade.

Taeyong was about to release another arrow when the demon burst into dust. Behind it, a heaving Jaehyun kneeling on the floor with his blade in hand came to view.

“What happened to you back there?” Taeyong asked walking closer to the younger.

“It looked like you,” Jaehyun explained.

“Jesus Jae,” Taeyong erupts. “You’ve been hunting demons all your life and you’ve been fooled by one just because it looked like me? What kind of idiocy is that?”

“I know... I’m sorry,” the younger said with his head hung low.

Taeyong stares at him for a while, his gaze piercing and despite Jaehyun being taller than him, he felt small under the elder’s eyes.

“I’m sorry too, I shouldn’t have blown off on you like that. But you really made me worry,” Jaehyun smiled weakly at him and Taeyong sighs observing his parabatai. Jaehyun’s blessed with fair white skin but his skin now is paler than usual, even his lips were turning white. “Are you alright?”

Jaehyun was about to nod his head when he remembers what happened earlier. He pulls his sleeve up revealing the bite mark the demon has left.

“You’ve been bitten and you didn’t tell me?!” Taeyong growled taking his stele out, Jaehyun hissed as the other pulled his arm and draws a healing rune on top of his scar. “I need to get you back to the Institute quick.”

Taeyong helps the younger to get back on his feet but before Jaehyun could take a step, he lost his consciousness and succumbs into darkness.

— - —

When Jaehyun regains his consciousness, the first thing he saw was the white ceiling and the fan hanging from it. He blinked a few times wondering what happened then the memory of the shapeshifter taking Taeyong’s form, him being bitten, killing the demon and everything that happened that night before he passed out flashed in his mind.

“You’re awake,” a familiar voice says, even without seeing who it was Jaehyun can already identify the person. He turned to his right and there, beautifully standing by the window, is his parabatai. Jaehyun’s breath was caught in his throat just by looking at how stunning Taeyong is with the sunlight on his face.

“How long was I out?”

“Just half a day,” Taeyong replied and slowly walked towards the foot of the bed Jaehyun is on. “Your wound healed quickly since I was the one who drew the rune.” Runes drawn by parabatai are stronger than any runes drawn by someone else.

“Thank you,” Jaehyun said whilst sitting up.

“No need to thank me,” the elder replied as he sat on the small space on the bed beside Jaehyun with a damp cloth on hand. “I took an oath to protect you with my life, remember?”

Of course Jaehyun remembers, he took the same oath and it’s one of the things he regrets in his life. Five years ago, a few months before Taeyong turned eighteen, the two of them performed a ritual; where they recited an oath and exchanged runes. Since then they’ve been bound to each other for life. Jaehyun was merely sixteen years old and all he wanted at the time was to be able to fight alongside his Taeyong hyung.

Where thou diest, will I die, and there will I be buried. 
The Angel do so to me, and more also,
If aught but death part thee and me.

It was part of the oath they took, that only by death would they be separated. But even then, when one dies a part of the other dies with his parabatai as well. Parabatai are bonded together in all ways but one… love.

It’s an honor for Jaehyun to be Taeyong’s parabatai. But it’s also a curse that reminds him he will never be with the person he loves. If he could take back every word he said, if he could remove the mark that binds the two of them, he would do all of it means he get to be with Taeyong in the way he wants.

It is written in the law, the Shadowhunter’s Codex, that falling in love with one’s parabatai is forbidden. It puts the bond parabatai’s supposed to share at great risk if one falls out of love. Aside from that reason, no one knows why it is written in the law. Some say it’s because of what happened in the past to a parabatai pair that fell in love. Others say it’s because love makes parabatai bond stronger and powerful than ever that it becomes dangerous. Another rumor say a parabatai in love are damned by angels. If it’s true then Jaehyun doesn’t care, he’d rather be damned and be with Taeyong than not at all.

Jaehyun stares at Taeyong while he gently dabs the towel on the younger’s skin. They sat there quietly, Taeyong cleans Jaehyun while the other watches him intently. It’s like they’re in their own world where nothing else exists except the two of them. No demons to hunt, no clave to follow, no downworlders to think of... just them; not the parabatai Shadowhunters, but simply Taeyong and Jaehyun.

Taeyong looks up only to be met by a pair of dark warm eyes, eyes that are full of longingness. He can’t help but think how badly he wants to get lost in them. Jaehyun takes the wet cloth from the older placing it down on the nightstand without breaking eye contact with the other. His hand reached forward caressing Taeyong’s face. Taeyong leans into his touch feeling the warmth of Jaehyun’s skin on his, calling him like home. Jaehyun wanted to close the gap between them but he’s scared of how the older will react. His moment of hesitation was all it took for Taeyong to get back to his senses, quickly he gets up on his feet, cheeks and ears burning red. He turns to leave but Jaehyun was fast enough to grab his arm and pull him back making him fall on the nephilim. Both their hearts were beating fast and it’s like time stopped. Slowly, the younger leans closer, feeling Taeyong’s hot breath and when the older didn’t flinch, he closed the gap between them, closing his eyes and pressing his lips against Taeyong’s.

Jaehyun’s lips were soft though a bit chapped. Taeyong knows it’s wrong but he wanted to indulge himself and drown himself in Jaehyun even just for a few minutes. Even just for a while he wanted them to give in to their feelings like any two young adults in love and not some warriors putting off their emotions. With eyes closed he responded to the kiss, parting his mouth and letting the younger’s tongue in. Jaehyun groaned softly, low on his throat, hands cupping Taeyong’s face. He could taste him, so sweet and addicting like a drug he’s craving but can’t have.

A few more kisses after and Taeyong puts his hand on Jaehyun’s chest, slowly pushing him away. He watches as the younger looks at him with a puzzled face. Quickly he averted his eyes, he couldn’t meet the other’s gaze as he was still flushed and embarrassed. “I-I g-gotta go,” he stuttered before running away like the coward he is leaving Jaehyun breathless with his heart hammering to his chest.

— - —

After that day, Taeyong distanced himself from Jaehyun. What they shared was a moment of weakness, a mistake they were foolish to commit, something that both could have prevented, but neither of them did. It was a one time thing and Taeyong can’t let it happen again.

To distract himself, Taeyong’s been training more, everyday he would spend hours in the training room shooting arrows and today isn’t any different. But so far none of Taeyong’s arrows have hit the target and all he could think of was a certain Nephilim’s soft lips and sweet taste. He’s always been aware of the feeling’s Jaehyun has been harboring for him but he chose to turn a blind eye. Not wanting to believe that the young boy who is like a brother to him feels the same attraction as him. Has the same forbidden feelings he’s not allowed to have not just because they’re both males but because they’re parabatai.

“You’re too stiff,” Taeyong was lost in his thoughts he didn’t notice Jaehyun’s arrival. He ignored the younger and continued shooting arrows. “You’ve been avoiding me and I think I know why.”

Again, Jaehyun was replied with silence.

“I don’t see anything wrong with what happened that day,” Jaehyun talked from behind. Taeyong’s breath hitched and shivers ran down his spine. He didn’t expect Jaehyun to be too close that he can feel his breath on his skin. Taeyong’s heart stopped beating when the younger placed his hands on his hips and started kissing down his nape.

“Don’t,” Taeyong threatened but Jaehyun chose not to listen, rather he on the juncture between Taeyong’s neck and shoulder, leaving a mark.

“We can’t,” Taeyong whispers though he wasn’t sure who exactly he’s saying it to.

He feels Jaehyun behind him as he rests his head on his shoulder. The hands on his hips moved, now Jaehyun’s arms are circled around his waist. “Hyung why did we do it?” he asked. “Why did we choose to be parabatai?”

Taeyong lets the younger hold him in his arms, even he doesn’t know why. Maybe it’s because of the idea that not everyone finds a person worthy to be their parabatai and he and Jaehyun are blessed to have found each other. Or maybe it’s the thought of them fighting together and protecting each other with their lives.

“Shouldn’t you be resting still?” Taeyong asked, changing their topic to something else.

“It’s not like it’s the first time I got bitten by a demon,” Jaehyun replied still holding on to the older. “Plus I felt lonely without you.”

Taeyong’s trying his best not to react to the younger’s comment but the beating of his heart is not something he can control. No matter how much he begged for his heart to be still, it still continued to beat erratically in his chest.

As if reading Taeyong’s mind, Jaehyun lifts his head from the older’s shoulder and pressed his chest against his back, not leaving any space between. “There’s no one else who can make my heart race like this.”

Taeyong closes his eyes, head resting on Jaehyun’s body as he listens the thump of their hearts, beating in sync. “Hyung, if loving you is wrong, why does it feel so right having you in my arms like this?”

Taeyong swallows the lump in his throat together with the last inch of self restraint he has. Turning around, he faces the black haired Nephilim, wraps his arms around his neck and captures his lips in his for a kiss.

It didn’t take long for Jaehyun to respond tightening his grip on Taeyong’s waist. Their tongues danced and teeth clicked as they shared a messy and hungry kiss, pouring every longingness they have for each other. Taeyong’s hands started to roam feeling the younger through his shirt, from strong arms to his broad chest and down to his well toned stomach. Jaehyun nibbles on Taeyong’s lower lip before moving to his jaw and abusing a column of his neck earning a gasp from the other.

Slowly, they both pulled away as they tried to catch their breaths. Jaehyun smirks, his heart swells with pride as he looked at the older Nephilim standing before him, breathing raggedly with red swollen lips and messy silver hair. Taeyong looked so wrecked and he was the reason for it.

— - —

After what happened in the training room, the pair shared more, one too many kisses behind closed doors. Holding hands when no one’s looking and leaving touches that stay longer than they should, but not enough to raise suspicions. Everything is going great, their relationship remained unknown. In the eyes of the public they’re parabatai, two of the best Shadowhunters that fight side by side. But within the four walls of their room lies the truth of what they are.

A month of bliss spent together passed by, Taeyong and Jaehyun just got back to the Institute from a night of patrolling the streets of Seoul. They were laughing at each other, once again lost in their own world, excited to retreat back in their room, when they were met by an elegant looking woman and suddenly the smiles on their faces fade in an instant. Her back was turned to them but it was still easy to recognize who she is, with her hair tied up, pearls around her neck and wearing a black sheath dress.

“Mom,” Jaehyun calls and the lady turns to face them, smiling as she