Disclaimer: I don't own Organization XIII. If I did, that would kick ass.
This takes place before COM, before Marluxia turned into an arrogant nobody. I know it might be a bit out of character, but I haven't played COM so I'm basing Marluxia's character on what I've seen here and on DA, which isn't much but I do what I can.
Of all the Organization members, Saix wanted his heart the most. Marluxia knew this. He also knew that, unlike the other members, Saix didn't fake emotions. He simply always had his trademark deadpan look outside of battle. Because of the fact that his emptiness was more noticeable on him than the other nobodies, Marluxia almost pitied him. Well, as much as a nobody could. Everyone else avoided him, the "psycho", but Marluxia didn't, and he wanted to do something nice for him. The only other one who would even approach the berserker was the Superior, but that was only when he had an assignment, as far as Marluxia knew.
One day, the terrible trio, Axel, Demyx, and Roxas got a pet cat. Marluxa wondered if it would be taken care of properly. How long would it be before it was neglected to be fed, or even worse, how long until it had the telltale burns from "playing" with Axel too much? At first, things seemed to go smoothly apart from Saix being grumpier than usual. His eyes looked red and puffy, and he began to sneeze every time this cat came around, or if the terrible trio came with their Organization cloaks covered in cat hair. Marluxia realized: Saix? With an allergy? Is this his weakness? Marluxia was surprised how helpless Saix looked when he was suffering with an allergy. To make things worse, everyone made fun of him instead of trying to help him.
Marluxia didn't particularly like what this cat was doing for everyone. It made Saix grumpy, which in turn made everyone else edgy as if the smallest thing could set him off, and it got the terrible trio into more trouble. Luckily for our Assassin, he always knew to lock his greenhouse so the cat couldn't mess with it. In fact he had always locked it after the time Vexen put a nice layer of snow on it, killing everything and making him start from scratch. Speaking of which, he hadn't even been to his garden that day, and he thought he should check on it just in case...he shuddered at the thought. He unlocked the door to his greenhouse and stepped inside to find something amiss. The cat was here and rubbing itself all over a particular plant- a catnip plant. The second thing he noticed was that there was a hole dug under the wall, leading to outside. This cat smelled my catnip and dug its way in here?! Marluxia thought, slightly confused. He knew the properties of catnip and that cats were attracted to it, but he wondered if it was a little much to actually dig so far to get to it. Marluxia picked the cat up with one hand and straightened out his catnip with the other. He frowned. It's not as perfect as it used to be, but it could be worse… he thought, a chill running down his spine remembering how cold it was that day. All of a sudden he got an idea. Looking at the cat, and looking back at the catnip, he thought of something nice to do for Saix.
Marluxia was a botanist. And when he wasn't taking care of the plants he already had, he liked to cross-pollinate and experiment to see what kind of bizarre plants he could create. He particularly liked dangerous ones, or ones that were beautiful but deadly poisonous. This time, however, he was going to make a variation of catnip. Or berserker-nip, as he was going to call it.
After putting the right ingredients together, giving it a bit of sunlight and adding a touch of magic, he had his berserker-nip. Now he just needed to give it to him. He wasn't quite sure how Saix would react to the herb, as he hadn't tested it yet and there was always the possibility of error. Then there was the fact that if he were to simply hand it to him, he might be given a strange look and the herb might be cast aside. How do I give him this without him knowing it? If I come right out and tell him what it is he might not approve… Suddenly an idea formed in his mind.
Saix's birthday was coming. Well, not that nobodies had birthdays, but it was the anniversary of Saix joining the Organization, which was as close as they could get. Marluxia decided to put together a nice bouquet for him for the occasion. It's not like he'd never done this for any other organization member, so it wouldn't be suspicious at all. He took a glass vase and put some moonflowers in it, which he knew was Saix's favorite, even though he pretended otherwise. He also put in some bleeding hearts, and to "fill in the gaps" he put in the berserker-nip. Marluxia could put together a fine bouquet, and he stepped back to look at it to make sure it was perfect. He put some water in the bottom and headed to Saix's room.
Saix heard a knock at his door, and opening it he found Marluxia with a vase of flowers. He wasn't quite sure how to take this, as he thought Marluxia to be one of the…stranger…members of the organization. There had to be a catch. Marluxia simply smiled and gave a "Happy Birthday!" as he thrust the bouquet in his arms. "Uh…" Saix began, but the gardener left before he could say anything. Rather, he left before Saix could realize what exactly he had been given. Saix took a moment to see what exactly he was holding. Moonflowers. As if that hadn't been overdone, but he secretly enjoyed their lunar power. Bleeding hearts…now that was a new one. He had to admit, they were kinda pretty. And they looked like hearts. Heh…maybe he's giving me a "heart". But what really caught his attention more than anything was the last herb. It was obviously a filler, but its smell was much greater than the others. He took a piece out and began sniffing it, trying to figure out what it was. The scent became stronger as he rubbed it between his fingers, releasing its essence. He started to get entranced by the scent and found it strangely…thrilling? Saix flinched at the thought as he noticed that his senses sharpened as they focused entirely on the strange herb in his hand. He felt a tingle down his spine and…wait, he felt? What is this…? Am I feeling this? But I'm not supposed to feel! As he wracked his brain with all the knowledge he had on the emotional capabilities of Nobodies, he became confused. Part of him wanted to storm back to Marluxia and demand to know what this vile thing was, and part of him wanted to roll around on the floor in the moonlight rubbing this herb all over his body. Wait, what? Saix shook his head and mentally ordered himself to snap out of it. What the hell is wrong with me? Is it just me? He eyed the herb carefully and weighed his options. If he asked Marluxia, he'd probably lie. Who else was there to ask? Vexen, who could identify it with scientific procedure? Zexion, whose sense of smell exceeded his own? Larxene, seeing as she was so close to Marluxia? Well, if Marluxia was going to lie, he should at least know what kind of lie. That sounded like a good place to start. He took one last long sniff of the herb in the privacy of his room, and with a deranged smile and cloudy eyes set off in search of Marluxia.