A/N: Spoilers for the Tartarus Arc and Chapter 414 onward.

On a side note, this is the first story I've written 100% on my cellphone, because my Muse dumped the whole thing into my head at three in the morning and I was too sleepy to get out of bed to type it.
Bookcover art by Nanaruko. fav. me/d62b93d

Understanding Arms

a Fairy Tail fanfic

by Rhov

Lucy was always trying to change Natsu. "Stop being so destructive. Don't jump in through my window. Stop eating up my food. Don't burn that! Get that out of your mouth. Try to be more serious. Act your age for once."

Lisanna held her tongue whenever she heard Lucy starting up again. People in the guild whispered that she nagged Natsu like a wife. Some went so far as to tease Lisanna that Lucy had taken over her job. Lisanna just smiled politely when they said that, but she knew that the biggest difference between them was that she had never nagged Natsu.

Sometimes, Lucy's harping annoyed others in the guild, but Lisanna figured that if it ever truly annoyed Natsu, he would speak up. He was not the sort of boy who quietly obeyed anyone.

Lisanna could not help but feel frustrated on his behalf, though. Lucy kept trying to change Natsu because she simply had not known him long enough. Sure, they were teammates, and it was nice to see Natsu working with a team finally instead of always on his own. Lisanna really wanted him to make more friends, she wholeheartedly encouraged Lucy to stick by Natsu, and she wasn't so naïve as to not realize that Natsu's immaturity meant someone had to bail him out of trouble. It could not always be Erza, and Lucy was perfect for that job.

However, Lucy had not known Natsu long enough to fully accept his habits. They had been together as a team from July until December, only half a year, before the incident on Tenrou Island. Then there were the seven years they all lost, so that did not count. When they came back, Natsu and his team lost another three months in the Spirit World. The Grand Magic Games had lasted only for a few days, and it was only a few weeks later that the whole issue with Tartarus hit, and Fairy Tail disbanded. They were all separated for another year.

So in essence, Lucy had only known Natsu for a few months, maybe a year altogether. On the other hand, Lisanna had grown up with Natsu. It was not just missions; the Strauss family had practically adopted the Fire Dragon Slayer. They spent years hanging out together. She raised Happy with him like a father and mother.

They trained together, ate meals together, and studied for school together. Although she was a year younger than him, Natsu's reading level was low when he first joined Fairy Tail. He learned fast, though. He acted like an idiot, but he was actually brilliant. She saw that side to him, the side that could focus on a book and learn it, all the time muttering that he would prove to Igneel that he could keep up with his studies.

Together, they managed through that awkward transition period called puberty, where bodies changed and feelings became complicated. She saw the wild boy turn into a gawky and blushing preteen, uncomfortable with his changing body. It was awkward for them both. She remembered when she first started her period, she was mortified to be around Natsu after he got worried because he could smell her blood. However, someone (probably Gildarts) explained it to him. Natsu came over to her house, where Lisanna was laid up in bed with severe cramps. He had placed his warm hand on her belly to ease the pain, all the while silently blushing and looking away from her.

She remembered that endearing moment. It had meant so much to her, just knowing that he would accept her changing body. They both knew that day, they were changing and things would never be the same, but they still had each other.

Soon, his voice changed. He changed. She saw him turn from a boy into a teen. He grew tall, his scrawny body began to fill out with muscle, while her body was changing, breasts growing, and hips taking shape. He often gazed at her strangely, only to look away in frustration. Mira had to explain it to her. Boys began to see girls differently, and definitely Natsu was starting to see her as a woman now.

Yes, they were apart for two years, but now she was back in time to see him growing from that callow teen into a man.

She remembered how he was when they were children, and she missed those days. When she returned from Edolas, he had matured. Maybe it was Lucy's influence, or maybe it was just time, battles, and becoming jaded to emotional pain. For how much Lucy griped about Natsu being immature and destructive, this was totally tame compared to the past.

Lisanna realized, she would not mind one bit if Natsu acted like his old, immature self once in a while … at least around her.

"Sheesh, Lucy! I didn't even get in trouble," Natsu finally shouted with an edge to his voice rarely heard in the Fire Dragon Slayer.

Lisanna saw it right away. He was annoyed; Lucy really should stop harping on him. Instead, the blonde began to list all the things he had broken in their last mission, along with how much each cost. With a growl deep in his throat, Natsu rose and stormed out of the guild hall.

Lisanna could not really blame Lucy. She had been raised in a proper setting, a grand mansion where everything was kept clean and orderly; whereas Natsu was raised by a dragon and acted just as wild as one. Lucy did not have family to help with expenses, not like Lisanna had Mira and Elfman; and Natsu did not pay rent for that cabin in the woods. Money was too tight to have a destructive teammate using up their reward money just to cover repairs.

Still, Lisanna hoped Lucy soon learned to let Natsu be himself.

She felt bad for him, so Lisanna sneaked off to follow Natsu. He was just being himself, after all. Lisanna knew that. Lucy was frustrated because now she would be short on rent money. She did not realize that not once had she actually been late. Somehow, she always had just barely enough money. She had mentioned this in the guild before, saying she was sure she was a thousand Jewels short that month, yet the money in her bank account was barely enough. She had no idea where the mysterious deposits came from. Before Tenrou, she had assumed it was her father, and it actually made her angry to think he was supporting her. However, those mysterious deposits kept happening whenever she was sure she would be short on rent.

Lisanna had seen Natsu go into the bank. She knew he kept his money at home, so she approached him one day to ask about it. Bashfully, he confessed that he was using the food money meant for him and Happy and giving it to Lucy since he knew he was the reason why she was short on rent. He explained, that was why they often raided Lucy's kitchen. They had no money for food, and sometimes they couldn't catch enough fish for dinner.

It was things like that which showed to Lisanna that Natsu had truly matured.

Following Natsu was practically impossible, especially when he was running. She was not faster than him, nor did she have his sense of smell, but Lisanna knew where Natsu would go. He always went there.

Outside of town, where the river flowed toward Magnolia, just outside Lilac Forest, stood a willow, old and gnarled, a tree that might have grown there when Mavis first arrived in Magnolia. Natsu stood within the drooping silvery branches, curtained from the world, staring off into the river. It was the tree he had always gone to when he was frustrated. When they were kids, she called it his "comfort tree." Lisanna had stood under that willow with him many times.

He had been coming here more often since Fairy Tail returned. Events leading up to the disbandment and things that happened afterwards all troubled him deeply, although he never let on that he was suffering inside. The death of Igneel hit him harder than he would ever tell anyone, even Happy. The issue with Gray, the whole business with Zeref and E.N.D., so many troubles they faced to get to this point … he went through them smiling like always. Then, when he thought no one was looking, Natsu came out to this tree to stare off into memories of the past, or maybe dreams of the future. Lisanna didn't know what those mournful eyes saw, and she never asked.

She knew he was already aware of her approach. There was no way to hide her smell. He did not move or snap at her to leave him alone, though. His silence was an invitation, so she carefully pulled back the branch curtain and stepped within, entering his world of mottled greens and silvers. Filtered sunlight danced in his narrow eyes and played over his skin, giving him the appearance of having dragon scales.

She did not say his name or ask him what was wrong. She had no need. She just looked at him, waiting for his stubborn pride to surrender.

"You're the only one who doesn't try to improve me, Lisanna," he finally sighed.

She took a step closer. "I've always known that I don't need you to change at all," she stated softly.

Finally, his stubborn arms opened and she stepped up against him. He grasped onto her like a lifesaver, and Lisanna held him, shielding him in a way no one else ever would; only her, the childhood friend who had always accepted him as precisely how he was.

"Growing up sucks," he grumbled petulantly.

She smiled that he would say that, when she realized that what she was hugging was not a scared little boy, but a battle-hardened man, muscular and tall, with eyes that had seen too much sorrow for their age. He had already grown up.

"You can always be a child around me," she offered.

He pulled back and smiled tenderly at her. Yes, she reminded him of innocent days, a time when he was idealistic, hopeful, so sure that he would reunite with Igneel, never questioning that Fairy Tail would always be there, not a thought in his mind that they might all separate one day. She had existed with him during a time of naïveté.

That was the nice thing about childhood friends: they were links to the past, they knew you best, they had seen you through all the awkward phases, and somehow they stuck by your side despite all that.

"Nah," Natsu smiled quietly, and he tipped up her chin. "Around you, I can't be a child."

She always thought he might kiss her, yet he never did. He never needed to. She understood, and so did he. Their bond was one that did not necessarily need to be romantic, although sometimes she dreamed it might be one day. Their bond went deeper than lust. They had grown up together. That was the sort of bond that did not break. Even if Natsu picked someone else to love, Lisanna knew that she would always hold that precious place in his heart, a spot no other person in the world could claim: she was his childhood friend!

Her clear, blue eyes were almost the same as when they were innocent children, unaware of life's tragedies. Except, those eyes were older, too. They were not totally the same as when they were kids. Natsu realized that Lisanna had experienced sadness and loss as well. Edolas changed her, made her mature. Still, in her blue eyes, he could forget his pain momentarily.

He did not kiss her, but he hugged her. Somehow, that was far more endearing than merely pressing lips together. A hug involved the whole body, not just the face. He held her tightly against him until she could feel the solid hills of muscles in his abdomen. She rested her cheek on his shoulder. She had always loved the smell of his scarf, and she nuzzled its warm folds.

She felt his nose rub against her hair. He used to do that as a kid, too. Back then, she thought it was gross to have someone smell her head. Now, she got shivers when she heard Natsu inhaling her scent. How did she smell to him? He never complained. Instead, he inhaled, and his body relaxed. It was endearing to know that she could give him comfort with just her familiar scent.

This was all he needed: this link to the past that grounded him as he struggled through the painful present and faced an uncertain future. She would be his anchor, so that he could fly as wildly as he wanted yet always return home. Maybe weeks passed, maybe months, even a year. Still, Lisanna knew Natsu would always return to Fairy Tail. He would smile, laugh, challenge others to fight, and when he needed to stop pretending that he was okay, he would come here.

And she would be waiting.

In her understanding arms, Natsu knew he could simply be himself.