Disclaimer: I do not own Eyeshield 21.

Rui Habashira was a master of pain.

He knew what it felt like to endure it, to give it, and how to avoid it. He wouldn't necessarily call himself an expert of torture, but if he was by any instance plucked from his current body and thrown into one of a feared commander in the Civil War, he knew he could learn the tricks of amputating and whips just as quickly.

While he never paid attention in anatomy class, Rui knew perfectly well where pressure points were. As human beings, natural instinct taught all creatures that in times of distress, an adrenaline-pumped punch could save them. Bringing pain was in the habit of a human. It wasn't a foreign concept to anyone – little kids learned to torture their peers by mercilessly tickling their kneecaps. Teenagers engaged in fist fights behind the school to claim something that was there's. Doctors never cringed when giving patients agonizing shots that harbored needles that were thick and lengthy. It was a human habit to take pain hard but give it just as roughly.

Killing was a different matter, but pain wasn't complicated in the least. It was survival, like tigers clawing at each other to win the prize of eating the flesh of a dead animal.

Rui wasn't by any means justifying his bullying. He knew he was a tormentor who was well known for his elongated arms that could squeeze anybody to breaking point. But he knew that hurting wasn't something he could force himself to stop. It was less of an addiction than instinct, which was probably why he had become so talented in intimidating his victims.

He did it for many different reasons; to threaten, terrorize, claim, the thrill, and on dreary days just for the hell of it. So it was an obvious understatement when someone declared that Rui knew his way around lethal instruments. It was not the move of a smart man to mess with him on any day of the week.

Rui knew more about physical combat than anyone. But unfortunately, physical combat wasn't much about physical combat at all. Calling them rules would be a definite stretch, but there were limits that Rui had slowly learned over the years that came with fighting. Not to fight against someone more powerful than him, not to engage in a war with someone who knew how to pull triggers, not to beat up women no matter how much they pissed him off… they were all things Rui had picked up on. And he stuck to them… ninety-eight percent of the time.

Which was probably why he had never brandished a raised fist in Hiruma Yoichi's face before in his lifetime.

Even Rui Habashira knew his limits.

O O O O O

Rui snickered in satisfaction down at his prey, whimpering and writhing on the stone floor while clutching a bloody nose. He tossed the chain in his right hand aside and unfurled his left, the whole time a suppressed chuckle seeping through his teeth. He nudged the wounded man with the toe of his shoe and examined his wounds. His shirt had ridden up to display already bruising ribs, his sleeves were ripped to expose scratches, and his ankle was bent at a painfully awkward angle. The man on the floor moaned again in agony.

The three other men all standing behind Rui like an eager audience witnessing the whole scene laughed in synchrony with him.

"That should teach you," Rui cracked his knuckles, smearing the blood running down his palm off on his sleeve, "not to mess with Rui Habashira."

His tongue snaking its way through his lips, Rui smiled and with one last kick, he motioned for his onlookers to take their leave as he shuffled away with his back a little straighter due to his ever growing confidence and his hands in his pockets.

"Boys, I'm getting rusty," Rui muttered over his shoulder, examining his hands, "better practice more tomorrow."

The men behind him chuckled in anticipation. Rui grinned over his shoulder.

O O O O O

The next thing Rui Habashira learned to put into his rulebook of combat was to never be caught. The victim was easy to subdue as long as their cell phone was crushed and they weren't traveling with a friend that would seek them out. He'd been caught with blood on his coat more than once, sometimes by police, sometimes by teachers, and sometimes he had been foolish enough to engage in a fight in broad daylight with the public watching him. Rui learned that running away from the scene of the crime was fruitless, and hiding was for cowards. In fight or flight, Rui had learned to choose fight.

It was the chameleon way to adjust their fighting style to whatever came along.

So when a stray chemistry professor went to investigate some strange noises they had heard, all Rui had to do was lure him closer and finally send a good kick in the shin his way before the wrinkly teacher crumpled like paper. It was a weak punch in comparison to the rocket he would have to send to the victim now cowering at his feet, but that was what the chameleons did; adjusted their fighting to what they needed to.

O O O O O

Rui had beaten up the Deimon guys before. Those obnoxious brothers, always walking in threes and wandering aimlessly into arcades; Rui had given them a piece of his mind before. He had roughed up that bookworm Yukimitsu before when he had been jogging for football practice outside of Zokugaku, but it certainly hadn't been a long fight. One blow to his cheek and the boy's knees buckled like his bones had to be duct taped to stay upright.

So after a hard day in math class, where Rui had gotten in trouble for trying to throttle the kid who attempted to steal his pen, he was in the mood for practicing his left hook. He strolled down the mall district by most of the local high schools, mostly keeping to corners and the darkest alleys in the crowded streets. His hands were stuffed in his pockets and his tongue kept twisting into an angry curl that slipped from his lips here and then.

Kicking empty soda cans as they lolled by the soles of his shoes, Rui grumbled softly under his breath when familiar voices wafted around the corner into his range of hearing. He paused for a moment, trying to match the voice with it's owner, and after a second's pause he corresponded them with two Deimon boys, Raimon Taro and Kobayakawa Sena. He sneered, his upper lip curling at the thought of messing with the two boys. In one swift step he rounded the corner and smiled eerily down at the students.

"Deimon," he greeted gruffly, his tongue continuing to snake and slither.

"Habashira-san," Sena peered up at the frightening boy through eyes that held an unhidden film of fear. His hands folded themselves together as he sent a shifty gaze to Monta beside him.

"Didn't think I'd run into you here."

"I'm sorry, Habashira-san," Sena apologized promptly, grabbing Monta's elbow and skirting past the older boy with a hurried speed.

Rui tutted at the cowardly action and swiftly shot his arm out to latch onto one of Sena's limbs. He pulled the small boy back, bringing with him Monta. Sena flushed furiously and attempted to hide his head.

Clearly his murderous aura had wafted over and although his exasperation was unspoken, the Deimon students had clearly picked up on Rui's frustration, hence their unmasked dread. He grinned down at them toothily and picked Monta up by the collar.

"It's a nice surprise," he drawled sardonically.

"H-Habashira-san, we sort of have somewhere we need to go–" Sena feebly pointed ahead of Rui, but his demand lacked strength. Rui scoffed.

"It can wait," he sneered, "I've been having a rough day."

Science proved that animals tended not to evoke fights in those that couldn't defend themselves; unfair fights were cowardly fights, and nature keeps even the cruelest of creatures from harming the weakest. A fierce lion, if trapping a meek mouse under its claws, won't swipe. It was inequitable and an unbalanced war.

Rui, however, didn't go by all science etiquette.

"I'm sorry, Habashira-san," Monta apologized, squeaking as his feet flailed uselessly in the air. Rui dropped him gracelessly onto the ground and turned his attention to Sena, readying his lengthy arm in the air. He poised his fist and took one swift aim at the recoiling boy.

For a second Rui thought that the running back had darted away with his impressive speed, as he had been known to disappear before even the sharpest eyes with his unmatched speed, but Sena was disgustingly loyal enough to haul the monkey with him. Instead of his victims vanishing, Rui felt a hand clasping around his forearm hard enough to rush all of blood into his wrist and stop all flows. Rui hissed and whirled around the face the person who had single-handedly stopped his punch.

"What the hell do you think you're doing, fucking chameleon?"

"Hiruma, you bastard." Rui spat, and wrenched his arm from the blonde's grip.

"Hiruma-san," Sena whimpered in pure relief, as though he had been saved from evil by another evil. Devil for a devil, but still, at least he had good ties with one of them.

"I asked you a question." Hiruma challenged, his face showing the lividness he didn't express with guns, but with an expression that killed crowds at a time. His eyes were narrowed into cantankerous slits and his mouth was tilted in pure disapproval. His hands were firmly set upon his hips and twitching slightly, as though itching to scoop up his guns and point it down Rui's nose.

But like Rui had learned, it was nonsensical to engage in combat with someone clearer stronger than he was. And Hiruma was everything and more than that. If there anyone Rui was terrified of, it was the devil glaring him down right now, bats' shadows fluttering over his shoulders. He had fallen to Hiruma's grip many times in the past, and more than enough to learn where he stood with the team captain.

"Just," he started innocently, "Having fun."

"Might want to find a new way to have fun, then," Hiruma snarled, and his hand wormed its way over to grab Sena's wrist and pull him away to safety.

O O O O O

To be told off by Hiruma Yoichi was like being told off by a stingy grandmother. It made Rui feel guilty about his actions, apologetic, but worst of all, scared out of his wits. He hated the loss of control and knowing that he had relinquished even the tiniest morsels left of it to a man who had enough power to rule kingdoms was enough to darken Rui's day.

More than it had already been darkened.

He snarled, grinding his teeth together and nibbling lividly on his tongue. The hands in his pockets fiddled with the lint on the bottom of them. He wanted to beat someone up, and being denied that privilege made him want it more. It was like a kid sneaking his hand into a fully-stocked cookie jar right before dinner when he wasn't supposed to and then caught right when his fingertips grazed against a chocolate chip. It was knowing exactly how close he had come to his goal and then being wrenched away. Expecting a prize and then being denied it made Rui even more aggravated.

"Habashira-san!"

"We've been looking for you."

Rui grunted and threw a disinterested glance over his shoulder, spying the three other boys from Zokugaku who hung around in his circle. They were an unimpressive bunch, incapable of intellectual conversations and teamwork, and always simply watched as Rui kicked the ego out of a big-headed basketball player roaming the school halls.

"Go away," he sneered, not in the mood for hanging with people that tended to heat up Rui's head.

"But Habashira-san–"

The boys had jogged up to Rui's shoulders by now, peering imploringly into his face. Rui pushed one of the boy's head out of the way and crushed it into the ground with his extensively long arm. The others gasped.

"Habashira!"

"Get the hell out of my way!" Rui grumbled, and when the remaining boys still stared in hurt at Rui's tense face, he growled and threw a strong punch in the left one's face.

The crunching of bones radiated off the halls as did the boy's wail of agony as he fell the floor cradling his chin. The other kneeled beside him. Rui scoffed and looked at the blood on his knuckles in distaste before smearing it off.

Without a second look back, Rui kept on walking.

He would ditch school today.

O O O O O

Hiruma's smile was etiolated as he stared after the fleeing Habashira. Even though his shoulders were high and tall, they were masking an obvious fright as Habashira hastened away. Rui was the worst type of cormorant; greedy and hungry for the feel of power even if he had to target weaklings such as Sena Kobayakawa. But luckily enough, Hiruma was always around to parry every blow, no matter how much of a virtuoso Rui was in combat.

"Hiruma-san," Sena murmured appreciatively up at Hiruma, the quarterback's arm thrown around Sena's frail shoulders almost in an obsessively protective manner.

"He won't be back, fucking pipsqueak," Hiruma dismissed automatically, the hand wrapped firmly around Sena's body tightening as it slipped down to his waist, "You okay too, fucking monkey?" Hiruma shot over his shoulder at Monta, who was following the pair like an extra tagging along.

Monta nodded, "Ughhh, yes, Hiruma-san… Habashira-san has gotten scarier."

"Or you've gotten wimpier." The blonde retorted, "Go back to practice, fucking monkey. We'll be joining all of you in a second."

"Hiruma-san," Sena mumbled, watching as Monta disappeared and Hiruma swiftly steered him into an alley.

Hiruma pushed Sena gingerly against the wall and pressed him into it firmly, his eyes smoldering, "If he pushes you around again," he growled, "you come straight to me, Sena."

It was such a rarity to hear Hiruma speak his name, so in the trickle of tingles running down his back, he smiled faintly and nodded.

"Good." And Hiruma pressed their lips together as though to seal the deal, his hand pressing hard onto Sena's hip and his teeth nipping in utter hunger.

"Oh, Hiruma-san–" Sena bit his lip to keep his moans from escaping and closed his eyes as Hiruma drew away from him, shifting his attention to his neck.

"That fucking chameleon better learn not to mess with us."

And being the first time Sena had ever heard his boyfriend speak of the two of them as one entity, he smiled and clutched back at Hiruma's body.

O O O O O

Even though hitting his peer had certainly improved Rui's bad mood, he definitely still had a thirst for watching someone squirm in pain. He wanted puny boys with wobbly knees and smooth hairstyles. It wasn't hard to find if he walked around the right schools.

Rui still had the desire to knock out the shorties from Deimon, but as long as Hiruma would be around he could forget about his craving.

"Fuck it." Rui growled, fed up with being horrified of Hiruma. He was angry enough to impair his better judgement, which gave him the false image that if push came to shove in the situation, he could punch out Hiruma too.

He stomped back through the streets until he located the neighborhood where he knew the pipsqueaks would hang out, having often seen Kurita joyfully leading the team along the sidewalk before to eat out together. He propped his hip up against one of the fences and tapped his fingers against his elbow as he crossed his arms and waited.

It took not that long before Sena showed up, seemingly Monta-less and lacking of any sort of supervision. Schoolbag slung over his shoulder, he trotted toward the house that Rui assumed was his own, not even aware of the Zokugaku player watching him from the corner. Rui made his entrance two seconds later, his footsteps bouncing off of the nonexistent walls surrounding them.

"Kobayakawa!" he said gruffly. Sena whirled around in shock.

"Habashira-san!" The obvious panic flew back into his expression. Although Rui didn't like to admit it, he enjoyed watching someone as feeble as Sena Kobayakawa squirm and wriggle in horror.

"I wanted to finish something I started earlier," Rui taunted, "I get mad when I can't finish something I started."

"I, uhm, see that, Habashira-san." Sena took a hasty step back, his palm beginning to sweat around his book bag strap.

Rui wasted no time beating around the bush, once again throwing his fist into the air and going straight for Sena's defenseless face.

He really should have known.

"Fucking chameleon, how many times do I have to tell you?"

Someone like Sena Kobayakawa was never defenseless. Whether it was that mother-hen Mamori Anezaki, or Monta the monkey to back him up, or the Huh-huh brothers who had actually become like protective teammates to the boy, Sena was always protected.

And besides, Hiruma Yoichi was everywhere all the time.

Rui growled. This time Hiruma hadn't blocked his punch by squeezing his arm to explosion point. He hadn't slipped in front of the running back as a shield. Rui's lack of self-control gave him half a mind to succumb to temptation and continue on with his hit. The other half, the logical part, was telling him to run away screaming while tossing repetitive and earnestly apologetic 'sorry's over his shoulder.

"One more time." He grumbled, and his fist flew.

Hiruma had never been blessed with an athlete's reflexes, so it astonished Rui when Hiruma darted in front of Sena with the reaction skills of a god, almost as though he teleported in front of the small boy. He stood in front of Sena, hands on his hips and his frown firm.

"Damn chameleon," he hissed, "you'd think that someone like you who's so skilled in fighting would know the first rule in combat."

No one insulted Rui Habashira when it came to his talent in war. His eyes bugged out, his tongue slithered, and his eyebrows shot up into hell.

"And what's that?" He was unable to control himself, asking the blonde anyway. Just for future reference.

"Maybe you can mess with a puny half-pint," Hiruma began, "but don't mess with a puny half-pint with a kickass boyfriend. Cause that kickass boyfriend will live up to his name."

Rui felt nothing but puzzling enigmas sorting through his brain. Kickass boyfriend?

"Then you better show me to this kickass boyfriend!"

Hiruma's scowl upturned to a heinous grin. He smirked, pulling a sparkling gun out of the back of his pants and pointing it straight at Rui's forehead. He snickered.

"You're looking right at 'im, fucking chameleon!" he threw his head back and laughed diabolically, "Scared yet?"

Rui froze.

"H-Hiruma?" He stuttered.

"Um, Hiruma-san, can I, um, go home now? Sena pleaded, tugging on Hiruma's sleeve.

"Absolutely not, fucking shrimp," Hiruma's hand snaked out and grabbed onto Sena's waist, furling his arm around his body and gripping him by the hipbone. Rui watched the exchange with eyes triple their original size.

"So you're going to answer to me," The gun still firm in Hiruma's grasp circled around his finger deftly before landing in his palm once again. His eyes glinted.

"He's your boyfriend?"

"That's right," Hiruma confirmed, the palm fused to Sena's side sneaking its way into his pants and playing softly with the ticklish flesh at his hip. Sena squirmed.

"I, um, I didn't know."

"You don't mess with my boyfriend, fucking chameleon." The team captain taunted, and without another warning he fired a single shot into the air. Rui tried not to flinch at the sound.

"I'm sorry!" He hastily blurted out.

"Apologize to him."

"I'm sorry, Kobayakawa!"

Hiruma grinned, "If you haven't learned your lesson yet," he began, "go ahead and try me. It'll be real pretty. For one of us."

Rui did the one thing a true solider never did; he ran.

No matter how hard they tried, chameleons couldn't blend into the devil.

Rui's crisp overcoat billowed after him as he clumsily escaped, biting his tongue the whole time to keep a whimper from being uttered. He was stunned to leave unscathed, but he knew that if he had lingered for any longer, that wouldn't be the case.

The sound of gunshots echoing off the sky haunted Rui all the way back to his house.

From then on, Rui Habashira's rulebook of fighting had rearranged its priorities.

Rule number one: don't mess with a boy if his boyfriend can mess with you.

AN: For those of you who instantly think I hate Rui Habashira, think again. I don't think I'd be able to write a story about him if I loathed him. I'll be honest though, and admit that I at first hated Rui and recoiled every single time I saw him, but now, he's one of my favorite characters and I absolutely adore him 8D

And the fact that he loves his fighting only made this story even more amazing… this was just waiting to be written, ladies and gentlemen…