A/N: This wasn't originally going to be posted here but there is a severe lack of SetoMary so I decided why not! Apologies in advance if it doesn't make sense, because I'm getting into a bad habit of that and I'm going to try and fix it as soon as I can but...
The first time they met, Mary had shrieked and fallen over, covering her face with her hands and Seto thinks this is a brilliant start to a lifelong friendship.
"Do you want to go outside?" He asked when she was no longer afraid, or when he suspected she suspected nothing more from him - a mere child in her eyes. He'd found that she was a little scared of men, when they ventured to the outskirts of the forest once, so he would not refer to himself as a 'man' just yet.
He would when he became the man she deserved, he pledged in his mind; a young child's ambition, and the kind of thought that had him grateful Kano couldn't go around reading minds himself.
"I do," Mary replied shyly, fingering the hem of her dress. "But I can't go far."
"Do you want to come home with me one day?" It was an innocent question, but Mary flustered.
"I-I, well, I don't think.."
He grinned reassuringly then, gently pressing his forehead to her own - hers is cold despite her red face - and he said, "You don't have to answer me now, but please think about it, okay?"
Mary only reddened further, shutting her eyes and breathing deeply.
She agreed, in the end, as she agrees to a lot of the things Seto suggests. He has some knack for satisfying her curiosity, and they both adore nature and the natural world more than anyone else could comprehend. Mary, possibly because that's all she's ever known, and Seto because it's all he can run to from everything he has known.
It was a beautiful balance, and almost; "A fairytale, huh?" Seto pulled her into their first hug of many, and released her with a bright beam. "I think so too. I'm so glad to have met you, Mary."
"I .. I'm so glad to have met you as well." For the first time, she looked him properly in the eye and they stared at each other, before smiling.
There were no more words.
But they didn't need words.
The first time Mary met Kido and Kano - his two other most important people in the entire world - Seto was well in his teen years, and Mary had shrieked and fallen over in the grace that he had come to know came with the Mary Kozakura package. She had been bowing extremely low to the two, and had bowed so far she bowled herself right over and Kano was in stitches of laughter before she could as much as recover.
"Don't be rude," Seto had chastised the blond, though the smile didn't leave his face.
"W-welcome to the Mekakushi Dan!" Kano had stuttered between his laughs, and Mary was preparing to launch before Kido came hurtling in with a fist to his face.
"Don't mind him." The leader of the Dan nodded confidently, hands on her hips as she stared down at the newcomer. Then, subconsciously, as if it were second nature, Kido's body moved to strike a cool pose as she extended a hand to Mary, "Nice to meet you."
"N-nice," Mary squeaked, in awe of the presence before her, and it took Seto nudging her forward before she placed her hand on top of Kido's. "Nice to meet you too."
This was the very first big step to expanding Mary's little world.
The first time someone mistook them for a couple was entirely Kano's fault. A lot of things are Kano's fault, Seto lamented, though he loved his brother dearly. Somehow or another, the blond had stuck a sign on Mary's back and written on it was -
"If lost, please return to Seto?" Momo had read aloud; the newest addition to the Mekakushi Dan, and possible candidate to sharing Mary's 'best friend' status. Amazing in many ways, Momo was, but she was right off the bat assuming things and more often than not embarrassed Mary in ways he'd never think of doing. A little like Kano in that sense, with the protectiveness of Kido. Seto, upon hearing his name, had turned curiously.
"Return what to me?"
"Mary." Momo had replied, before her face split into a grin. The idol lifted Mary's hoodie so the sign was fully visible. "Ooooh. Okay then."
Mary was frantic, trying to pry the sign off herself, but ended up tangled in her own hair. Seto, walking around, found his own satisfaction after contemplating the sign for a few moments and laughed, prompting the medusa to send him a sharp look, gesturing for him to twirl around. Apparently, Kano had gotten around to him too.
"I am Seto, property of Mary." She read, eyes narrowing ever so slightly. There was a glint of amusement, before she frowned at it, "What's that supposed to mean..?"
Seto only laughed harder into his hands, trying to muffle the sounds of embarrassment and elation in the one action. Not gonna lie though, it was also in fear of angering her. They had lived together long enough to know what an angry Mary looked like - and cute as it was, it was also rather terrifying.
"Seto!" She protested weakly, trying to escape her hair. Still laughing, he shuffled over to her to help, smoothing the creases in her dress from the struggle.
Momo watched them with bright eyes, before suddenly shouting: "Get married already, you dorks!" And sprinting upstairs before either Mary or Seto could react.
He swore - and he rarely ever did so but this was probably true - that he was an awkward, bumbling, run-off-at-the-first-sign-of-being-left-alone-with-Mary young man for weeks after that.
It wasn't that he hadn't ever thought of Mary romantically, because he did think of her all day, all the time (shush) but no-one had ever really brought it out in the open. Kido constantly muttered things like, "The lovebirds fell asleep at the furniture store and we had to go all the way back to find them" and "Seto, as her boyfriend, you have the duty of keeping her away from the blender", but he had always thought she had meant it as a jest since Kido enjoyed her little jests.
At least he thought she did.
Apparently, Kido was serious.
The first time Mary had visited him at work resulted in him working overtime for doing absolutely nothing while she was there.
"Seto!" Mary had greeted enthusiastically, practically rolling to him where he caught her in his arms and they hugged.
"Hi there," He replied, nuzzling her.
She giggled, while Seto's co-workers watched on in confusion.
"You work so hard." Mary commented, sauntering over to the benches and scanning over everything with a keen eye. She clapped quietly, "It makes me want to work hard too!"
"You are working hard." Seto grinned. "Just in your own way. Don't stress yourself out, you know?"
"Ah," Mary puffed out her cheeks, "But I want to help Seto too!"
"You do help me, lots and lots." He ruffled her hair. "Don't worry about a thing."
"You don't get it..." The medusa clung to him nevertheless, and he blatantly ignored everyone's stares as he got to work.
And when she finally left, he didn't hear the end of it.
The first time they had sung together came in a bundle with the first time they kissed. Someone had gotten them drunk at karaoke - not pointing any fingers here, but the bartender looked suspiciously like a certain blond that they knew - and in the height of crying through an emotional duet, Seto had swept the small girl into his arms and sealed her high note with a kiss.
Momo had taken five hundred thousand pictures (thank god that was an exaggeration, but she might as well have), and they all coexisted on Shintaro's phone where Ene was having a ball. Neither of them remembered the incident, and wouldn't have believed it if there was not sufficient evidence, but like a lot of things, it soon got lost in the seas of time.
Seto found himself reluctantly envious of his own drunken self, for having the courage to do that, but he'd realised his feelings and they would work it out over time.
The first time they had really, properly kissed being fully conscious of their actions was in fact, in the rain.
"Do you want to go see my mother?" Mary asked, on a stormy day with her hands clasped tightly around a travel card.
"I'd be honoured to," He cheerfully answered, cancelling his work for the day with a single phone call and they were soon on the 10 o'clock train. Without a single care for the muddy ground and the overgrown grass spilling from all sides, Seto sat himself right in front of Shion Kozakura, bowing his head in greeting.
"Hello, it's Seto. Seto Kousuke. Do you remember me? It's been a while, Mama Kozakura. How have you been?" He grinned, patting a flower onto the top of the wet stone. "I hope you're doing well."
Mary sat on his lap, holding the umbrella above them both with both hands and peering at her mother's grave with a small smile. "Hi Mama, it's Mary. I missed you."
"I've been good, just so you know." She continued, with a little encouragement from her companion. "I've made .. a lot of new friends. It's a lot of fun. But... I still.. I really miss you ... and I .."
"Smile, Mary." Seto piped up gently, wiping the first of her tears away. "Your mother would be so proud of you right now."
She did.
But it was only after they had gotten home in the evening, about to proceed inside when she had rose to her tip-toes and tugged his goggle straps down so his face met hers. A sweet, pure gesture.
The first time was a term they could use to describe many things. The first time Seto taught Mary how to ride a bike, the first time they shared a bed, the first time Mary had a birthday party and the first time they had shared nightmares and dreams over a pot of tea.
The first time they had cooked together, the first time they had drawn a big picture together - and framed it for the kitchen, gifting it to Kido. The first time they had gotten Kano back for one of his pranks (then apologised profusely, as it was in their nature), and the first time they had attended one of Momo's concerts.
The first time they made a flower crown for Ene in Shintaro's massive monitor, and the first time they had babysat Shintaro's rabbit for a week. The first time they had tended to a sick Hibiya, and the first time they had adopted Konoha as their exploration buddy.
The first time they had bathed together, the first time they had danced together - the first time they had made a blanket fort, and the first time they had camped outside.
The first time, the first time...
The first time he felt himself engulfed, helpless, slipping -
Slipping away from her grasp, eyes fluttering, pain searing through his limbs -
Choking, spluttering with an inelegant groan -
The first time she was screaming, "Stop it, please stop it, oh, god, why?"
Because for the first time, she had let herself love again and it was fading away ;
And suddenly all the other firsts didn't matter anymore.
"If you love him..."
The first time Seto had died, he had left a part of himself behind.
"... use your monstrous power."
His heart, of course.
"I want to see them again."
But that was just the first time, the very first time.