Disclaimer: I own neither of the characters involved else there would likely be in-game scenes hinting at this pairing. All that's mine is the writing.
Despite his place just below Saix in the chain of command, Xaldin was nowhere near as commanding as he presented himself during meetings. He was, in fact, a collared submissive. His front was something that he and Xigbar had agreed on to make their relationship seem more normal to the others than it was. It was just a face that the Lancer was showing on orders from the other Nobody simply to avoid the stigma that would likely be aimed their way if it was found out. Thankfully, they still had the cover of their numeric ranks to shield them if they slipped up and they had let it slip before.
The most memorable incident had occurred in front of Lexaeus. Number II had been somewhat impatient in his advances and had the Lancer at gunpoint. There were several tears in the dragoon's coat, he was evidently bleeding in a couple of places, and he was grinning broadly as he asked, "Care to remind me again of what it is you're trying to get?"
The marksman had drawn closer, pressing his weapon up against the other ready to fire, and answered, "You, chained up, bloody, and mewling for more."
The earth master had been unfortunate enough to turn a corner in the hall just in time to hear the response and witness the unusual scene. Saying nothing, he'd slowed to a stop to simply give his superiors a puzzled look. Xaldin, from his position against the wall, had noticed and cast Number V a glare warning of dire consequences should news of the incident ever get out. From there, the Lancer proceeded to open a corridor to darkness and pull Xigbar and himself out of the hall. Word of the occurrence had never gone beyond the three.
As a submissive, the Lancer was somewhat susceptible to suffering from withdrawal symptoms when he and the sniper were separated. To keep Xaldin from falling inactive while he remained in the castle, and because he had earned the trust of the two, Lexaeus had been recruited to keep tabs on Number III and give him orders as needed. The wind master recognized very few others as worthy of the position of a dominant and was unwilling to trust them as such, so the Hero was really the only choice.
When Xaldin himself was out on a mission, things were considerably more complicated. He had the willpower to keep at his assignment for some time, recalling that the smaller Nobody would want him to give the task his all. He was good enough at masking the wear from being separated from his Dominant was hidden while he was dealing with others, but left on his own, the Lancer found himself focusing on little details and what he missed from the castle. There was little that could be done to remedy such instances.
The Lancer sat on the roof of the Beast's castle, feet dangling off over the edge. His head was bowed forward, his eyes closed, and his hand was wrapped tightly about a small item. His grip loosened, fingers sliding off of the object, and his thumb trailed over its familiar features, the letters that meant so much to him. The words on the tag marked him as property and served as a reminder that he was owned y someone that would do his job as a Dominant and make sure the dragoon was well cared for.
Opening slowly, lilac eyes looked up, out towards the clear sky, focusing on familiar patters of stars. After a long moment of gazing out at the myriad specks of light, Number III allowed himself a resigned sigh. He had been working on this particular assignment for quite some time now. Having witnessed the arrival of the Keybearer and the undoing of a great deal of effort, the dreadlocked Nobody understood that he would have to remain there for even longer. Xemnas had said to sow some seeds in the boy's path. Even before interpretation, such an order implied that there would be much more effort put forth.
Falling into his thoughts, both of his mission and how long it had been since his last memorable encounter with his partner, Xaldin subconsciously created a small air current about himself. It would occasionally pick up, catching and lifting the drawstrings of his coat, but the small clinking noises as they moved went unnoticed. Something else that the Lancer missed because he was so focused was the brief appearance of a dark portal behind him, heralding the arrival of a somewhat smaller figure. The newcomer was visible for only a moment before vanishing, disappearing completely. Several second later, though, there was a voice. "Does someone need to be reminded of why he's still here?"
With a start, Number III straightened and looked up. He consulted the air currents for some sign of his visitor despite knowing that there would be none until the other decided to show himself. The response of the dreadlocked man was slow in coming, thought out. "Perhaps he needs something to keep himself going instead."
He took a moment to slide the tag he'd been holding back into a pocket and was rewarded with a more pensive statement. "I might make that effort…if you prove that you deserve it." There was a brief pause as they took a few seconds to consider the words. "You know how, of course. Let it show, Xaldin. Let it all show." The drawled out order was accompanied by a brief appearance of the elder man's hands under the Lancer's coat, dragging nails up along the wind master's back.
The Lancer's body reacted to the attention, the sharp nails that were digging into his skin, and his back arced forward. Before he could have stopped it, even if he'd wanted to, the dreadlocked man had given a small gasp. His mind very firmly planted in the present at this point, Xaldin realized that it was a good thing he'd opted to sit. His knees would likely have given out if he'd been standing.
Without warning, the rest of the space master appeared. He was perched just behind his larger partner, pressed up against the dragoon's back, and had his head tilted forward to where the younger man's ear was within easy reach of his mouth. The sharpshooter gave a low purr of, "I think that was a good enough answer," before latching his teeth onto the lobe ob the Lancer's ear. His tongue casually played with the silver earring and, in response, the larger man gave a quiet groan.
Xaldin started to turn towards his partner, his owner, hoping for more contact and was pleased to find the older man's lips meeting his, having vacated their claim on his ear and skilled tongue already questing for entrance. Holding to his position of submission, the Lancer allowed passage and gave a small sound of enjoyment as the marksman's tongue slid over his.
When they pulled apart, Number II holding his subordinate back with a hand, breathed a slow complaint. "Xigbar…" It was a brief pause, only the time it took for the sniper to shift into a more comfortable position. Then Xigbar's nails were dragging along skin again, sending pleasured tingles up the dragoon's spine.
When the Freeshooter finally left, Xaldin's energy was temporarily spent and he was far more relaxed than he had been in a week. He lay back on the roof, coat open he breathed deeply. They had taken care to leave no signs of their interaction outside of bruises and bleeding. Giving a low, quiet purr, the Lancer silently thanked his superior for taking the time to care for him. It wasn't much later that the large man fell into a comfortable sleep.