Grimmjow still recalled being present at the 'meeting' that the espada had been called to when a new initiate was welcomed into their little clique, taking the impressive rank of fourth when being a completely new face. Thin, lanky and the most pale man he had ever seen, his face seemed to be the definition of melancholy and his actions were every bit as nonchalant.
Despite his lack of an interesting personality though, his power was absolutely suffocating.
The image of those piercing turquoise eyes staring at him with disinterest as the reiatsu flared wildly around the room in a little demonstration had burnt itself into Grimmjow's memory, something that he recalled every time he saw the newcomer.
And, it was at this first meeting that he decided that he despised him. It was as easy as that; the bastard had been fed from Aizen's palm and then been awarded such a prestigious position without as much as lifting a finger. There hadn't even been any gratitude or response after he had made it there, either- just an inclination of the head as if he were too good to speak to any of the others in the room and sarcastic conversation whenever he was encountered in the halls.
Ulquiorra was without a doubt one of the most annoying people he had ever met- a lapdog to the king without an opinion or a mind of his own, the kind of person that wouldn't blink twice as they turned their sword viciously in your gut.
Grimmjow had never been a big person for emotions, being such a cocky and temperate individual himself, but the idiot could show something, and get the fuck off of his pedestal to mingle with the commoners to do them all some good.
---
They often passed in the barren corridors of Las Noches soon after that, usually on their way to carry out various errands for the white overlord sitting patiently in the throne room.
Grimmjow always stared at the horned man in distaste and disgust as they walked past, refraining from making a statement lest he lose control and end up having to repress an urge to get the other to make friends with the tip of his zanpakutou. Sometimes, Ulquiorra liked to say something in his monotone voice as if he were trying to push the blue-haired man over the edge, or getting him to do something that would land him in trouble with their superiors.
You could never say that he had any ulterior motives, though- it was always so disguised by the fact that his voice was completely devoid of any form of emotion or feeling.
Perhaps that was one of the things that pissed Grimmjow off about him so much. He didn't even seem like one of them, and there was already some pretty serious diversity in Hueco Mundo.
He wasn't natural.
Anger was real, pain was real.
How come he had never seen that tear-streaked face contort in rage, or a flinch as a blade was raised against him? Was he completely incapable of both of those things? Or was something so normal 'below' him?
When he next heard the persistent taps of sandals echoing down the hallway he was in, and a familiar reiatsu flood his senses, Grimmjow finally realised that he had to find out.
It was almost obsessive- he couldn't get the thought of the poison that Ulquiorra was spreading throughout Hueco Mundo out of his mind, and he had fitful thoughts of inflicting various forms of pain and misery upon the smaller espada as if it were satisfying to try and figure out what weakness he had; if he had any.
A white mask perched upon an ashen head came into his view, the same blank stare being awarded to him as his colleague neared, alabaster hands shoved carelessly into the pockets of his hakama like they usually were. Grimmjow, however, stopped where he was, his fists curling instinctively into balls by his sides as the other arrancar moved to walk past him whilst still studying him with something that looked like contempt and then paused.
A moment of silence passed between the two as both waited for the other to make the first move, the dark-rimmed eyes ever watchful as the other fought with himself to decide whether he would carry out his little experiment or go along on his merry way instead, abiding by the rules that 'Aizen-sama' had laid down for them.
And then, the alien decided to speak.
"You look rather unoccupied. Don't you have something better to do?"
It wasn't even that provoking, but enough to set the espada off, something snapping in his mind as the decision was made for him. As soon as the pale lips closed back together, Grimmjow's arm came up in a flash and connected immediately with the right side of Ulquiorra's jaw, the sudden blow sending the ivory-skinned arrancar straight into the wall of the hallway.
Plaster cracked and dust plumed into the air as he hit it with such a force, taking a moment to clear before Grimmjow peered through it with a venomous look- only to see the same blank eyes staring back at him in some sort of amused surprise, not a shocked expression of pain like he had been hoping for in a sadistic fashion.
"That was a little unexpected. You really should learn to control your temper."
Ulquiorra's voice floated over from across the rubble as the espada made to pick himself up and brush off the debri that had attached itself to his robes from the impact. Rage slowly welled up inside Grimmjow, his hands balling into fists again out of habit as he strode over to the other whom was acting like nothing had happened.
A palm shot out and grabbed the neck of Ulquiorra's jacket and a murderous set of cerulean eyes bore away at the paler man as he dragged him up mercilessly from the crater in the wall. With a flash, his zanpakutou was drawn and at the throat of the 'enemy' that annoyed him so much, the tip barely pressing against the skin below his face but even that hair's breadth was enough to draw a drop of blood.
Grimmjow almost expected it to be white, like the rest of him.
"Let me tell you now, that the rest of your existence here at Las Noches will be personally made a living hell by myself."
Was all the blue-haired man managed to grind out before sheathing his blade again, almost admonishing himself for drawing it on such a useless person.
There was another brief silence before Grimmjow dropped Ulquiorra harshly to the ground and walked off down the hallway before someone found them together, leaving the shorter espada to pick himself up again and absently finger the spot where the other's sword had drawn blood.
"It's unfortunate I've succeeded in doing that to you, already."