A/N: A AU set in the world of Cassandra Clare's The Mortal Instruments world. Natsu and Lucy are shadowhunters of the Magnolia Institute. Based on phantombones' Shadowhunter AU art on tumblr.
Natsu and Lucy halted in front of Natsu's room when Makarov called their attention.
"Get in your gear. There's a young werewolf in the plaza." Makarov Dreyar, head of the Magnolia Institute announced. "It's not a member of a pack yet. We need to go before it causes more trouble."
Natsu cracked his knuckles. "Alright, time to kick some Downworlder butt!" he said excitedly.
"No need to get so loud, Natsu." Lucy complained. "I know you love to fight but tone it down a little, will you?"
Makarov sighed a little. Natsu and Lucy are the only available Nephilim in the Institute at the moment. Erza and Gray are currently in Idris for a special summon from the Clave. He just hopes nothing worse happens. Most of the times Natsu goes out for a mission, he comes back bringing more trouble. It's only until Lucy joined in the Institute and became Natsu's partner that the boy mellowed.
"We'll go out in 10 minutes. Hurry up with your gears and Marks." The old man turned and headed to the front door. "I'll wait for you outside."
Natsu waited until the door shut. He faced Lucy with a lop-sided grin, "Will you help me with my Marks?"
"Of course." Lucy answered. "Help me with mine too."
"No problem."
Natsu opened the door to his room. Lucy quickly followed him inside. He reached for his stele on his bedside table and handed it to Lucy. He turned around and slowly lifted his shirt so Lucy can mark him.
Lucy's throat suddenly got dry at the sight. No matter how many times they do this, watching him undress still left her a bit uncomfortable. Thankfully he was not facing her or he'll definitely tease her for blushing. She swallowed and gripped the stele hard.
"Can we sit down?" she asked.
Natsu plopped on the floor quickly. He rested his arms on his knees and slightly curved his back.
"I meant on the bed. Never mind." She kneeled behind him and adjusted to find a comfortable position to work. She looked at him again. She almost swooned at Natsu's hard, toned muscles when he moved to flex his back a little.
Slightly shaking fingers touched Natsu's back.
Her pulse quickened as she felt Natsu's hot skin on her fingertips. One of the mysteries of Natsu is that his body always feels hot. It's like Natsu has a constant fever. Whenever they talk about it, he just shrugs and say "I guess I'm just hot like that."
Natsu inhaled sharply, surprised by the prick of the stele against his skin. He soon relaxed as Lucy started to work on his skin.
She started working on the Agility rune, one of Natsu's favorite marks. Her hand wrote fluidly, experience guiding her hand. She worked with the same flair for the other marks.
"Wait." Natsu said, breaking the silence. He shifted and turned around to face Lucy. "Put some marks on my chest too."
He captured her hand holding the stele and positioned it above the light scar of the Strength rune. Lucy blushed at the unexpected contact and looked away to hide her burning cheeks. "You could do them yourself, you know."
"Nah, I'd rather you do them. I like it that way." Natsu grinned at her, eyes twinkling with mischief.
"We're not parabatai. There's no difference when I mark you and when you mark yourself." Lucy grumbled.
"There is." He insisted. "And thankfully we're not parabatai." He added in his mind.
Lucy shook her head, giving up on arguing with Natsu. "Whatever you say."
"Thanks." He grinned again.
Lucy resumed her task and drew the Strength rune. It took a lot of concentration to keep her mind from getting distracted with Natsu's enticing body in front of her. "Keep yourself together, Lucy!" she reminded herself. She traced the other marks on his skin, her fingers brushing on the Natsu's skin.
"There. I'm finished." Lucy announced. "My turn."
Lucy handed the stele back to Natsu. She turned around and sat in a way similar to Natsu when they started.
She lifted the back of her blouse, exposing her bare back to the cold air. She might have heard Natsu inhale sharply behind her. She did not fully undress like Natsu did. Just exposed the skin where she would be marked.
She was pleasantly surprised by the warmth that came with Natsu's fingertips. It was not burning hot, but it did make her feel like her skin is on fire. The prick of the stele startled her, and then she felt his smooth strokes, dipping and varying in pressure for each mark. She would unconsciously hold her breath once he starts on a new mark until he finished and moved on to the next.
He has this habit of touching his handiwork once in a while. She could feel him skimming her skin over the fresh marks he made. She'd be lying if she says she does not enjoy the feeling.
She gasped when Natsu suddenly embraced her, his toned arms sliding down her own. He rested his head on her back, his breath tickling her skin.
"I give up. You just smell sooo nice." He murmured on her skin then inhaled deeply.
"Natsu." She whined. "Stop it. Finish my marks."
"I'm done. The marks you had last night for that quick mission are still here." He slowly wrapped his arms around Lucy's waist and kissed her on the nape.
Blood rushed from Lucy's head up to her chest. She groaned as Natsu's lips travelled from her nape to the side of her neck and left an open-mouthed kiss. "Natsu." She whispered again. "We don't have time for this." She rolled her shoulder a little as a protest.
Natsu sighed. "Fine." He moved away from her neck and planted a quick kiss on her nape again. He pulled down her blouse to her back and patted her back.
Lucy slowly turned around to face him, desperately trying to hide her flush under her fringes.
"Thanks Natsu."
Natsu chuckled and pulled her close. "Come here." He wrapped his body around hers, confining her in his arms.
He touched his forehead against her and looked at her straight in the eye. She marveled at how beautiful his brown eyes are with long lashes that did not seem fair to be in a man. His eyes were smiling at her, both showing mischief and longing.
He moved closer, touching his nose with hers then finally, kissed her full in the lips.
It started as a light kiss. He was waiting for her reaction. When she kissed back, a soft groan escaped his lips as she wrapped her hands around his nape. Meanwhile, his hands rested on the small of her back, pulling her closer to him.
She was not sure how they got so intimate with each other recently. All she can recall was that they were out in a mission to exterminate a rogue demon in the Magnolia Train Station one day. The fight had been rough, both of them full of scrapes and scratches. When they finally managed to slay it, they were both tired with worry for each other. Lucy ran towards Natsu and hugged him tight. A few moments passed then suddenly he was kissing her. It may have been a spur of the moment, emotions unchecked, causing both of them to act impulsively.
Thankfully, things never got awkward between them after it happened. If nothing, Natsu got treated her better after their first kiss. He was always near her, never letting her out of his sight. He protested every time Lucy goes out alone and insisted that he'd go with her. The first kiss led to more stolen kisses, more shy touches and hugs. And now, here they are in Natsu's room, kissing again.
Lucy pulled away quickly, panting as she filled her lungs with air. "We have to get in gear. Makarov's waiting for us." She rested her hand on his shoulder, putting a small distance in between them.
"Okay." Natsu's voice was a little gruff. He pulled away from her and stood up. He offered his hand to Lucy.
Lucy accepted the extended hand and felt herself being pulled to stand.
She couldn't help blush again as she felt his lips on the back of her hand. It was where her Equilibrium rune was placed.
She pulled back her hand. "Let's meet in the hallway. I'll get my gear."
"Sure." Natsu smiled at her as she left the room.
A/N: You can check out the beautiful artwork this one-shot was based from on phantombones' tumblr account ( .com). It was fun writing this and I hope you enjoyed reading it as well.
