I wrote this for the OP fan-for-all prompt, "Vergo defeats Law and brings him to Doflamingo for some insane, brutal fucking." It has been slightly edited.
Warnings for rape, rough sex, threesome and double penetration.
Despite his dark skin, Law bruised very prettily - the simple result of an equation where enough force was coupled with the complete absence of care one might come to expect. Under typical circumstances, Doflamingo wasn't one to use carelessly, but these were not typical circumstances. Law had made him very cross indeed.
He drew the little upstart brat against him. Law's limbs were weak, unresisting. It had taken a good deal of time to render him so, time that had been spent quite enjoyably in the use and breakage of his body and spirit. The manhandling earned him a dark glare, and it pleased Doflamingo greatly that the boy wasn't so far gone that he couldn't hold onto his hate. Let him keep it that way, helpless and ruined, unable to do anything as he was shared between enemies.
Vergo had brought him back from Caesar's laboratory, defeated completely though Law would never admit it. That was why this current lesson was required: Law had for too long assumed himself equal to his betters. It was why he'd gone out and claimed the title of shichibukai, so he could look Doflamingo in the eye and pretend that the title granted him equal footing in the world's power structure. He was wrong, though it'd been to Doflamingo's great amusement to watch Law struggle to prove himself. Law's ascension to the shichibukai spoke more about that archaic institution's rotting core than his own abilities. Law had never realized that truth; fortunately enough for him, Doflamingo was a patient man and these recent minor acts of rebellion had earned Law quite a few remedial lessons.
"I thought you were so special, my dear," Doflamingo mused. He arranged Law in his lap; the poor little broken thing had been used so thoroughly that he was positively dripping in ejaculate. "I fear such praise simply went to your head."
Law's mouth was gagged though his eyes spoke with black clarity. The seastone collar Vergo had fitted him with kept him weak and pliable; he'd been unable to mount a serious resistance ever since they'd started, though he did try. It was pitiful to watch. Whenever he made a concerted attempt, it was a simple matter to neutralize and Doflamingo hardly needed to use his own abilities at all. For someone of such slight physical stature, Law ought to have compensated accordingly.
One of many lessons to be emphasized in the coming months. With Law back at his side, they had much to catch up on - and there was much for the insolent brat to answer for. He pulled Law onto his cock without bothering to ready him further; the slick from before and their own leavings had left him open and wet. After so much use, his hole had been rendered raw and puffy though his body remained as tight and enjoyable as ever. Law made a choking groan, biting down on the cloth gagging his mouth. His hands feathered against Doflamingo's stomach, trying to find purchase. It'd been pointless to restrain him beyond the kairoseki collar, and Doflamingo liked watching him grip and tear and grapple; he liked the way Law's fingers knotted helplessly in the bedsheets when he was being fucked and he liked holding both slight wrists in one of his own hands, pinning Law down.
Moving inside him produced a vile, sucking sound that had Law flinching, as though he would cover his ears if he could block it out. It figured; both Vergo and himself had come inside the brat so many times that he was wet as a whore. He'd let Vergo have him first: he'd done it the way a pitbull would take a bitch, with Law's ass high in the air and his face pressed into the mattress. Vergo's armament-hardened body had fucked Law raw, a relentless, much-earned punishment for his cocky insolence.
Once let up to breathe, Law had let loose with such a cascade of profanity that the gag had been necessary - that was, at least until Doflamingo wanted his mouth. Teeth had been an issue, but the judicious use of his fruit ability had rendered Law's resistance as ineffective as always. The hatred burning in the little shit's eyes had truly been a thing of beauty, on his knees with his mouth stretched wide over Doflamingo's cock. Sometimes it really was amazing how much a human body could take when so forced, and Law proved to be no exception.
Respect was something that could only be learned in certain people. Law had never been much of a quick study for it, and Doflamingo realized that, in the past, he'd been foolishly sentimental in sparing the boy. Oh well; Law's best attempts in undermining him had all been for naught, and Doflamingo was quite enjoying rubbing the brat's face in his defeat.
There were bruises dotting the insides of Law's thighs from rough treatment before, though his hardened prick didn't seem to object. Doflamingo took him slowly this time, rocking Law over his considerable girth, the pull of his still-tight flesh enjoyable as ever. Unlike before, this current release was not something to be hastily chased; it would be hard-won after coming so many times already. Despite all that, Doflamingo was ever the patient man.
Even though Law resisted, there was little he could do to deny the physical responses that were carefully coaxed from him. He'd been made to come until nearly breathless: sharp, racking sobs all he could manage while trapped between them, one at his front and one behind. Vergo hardly saw the point in it but Doflamingo knew there was no better betrayal for Law to suffer than that of his own body, turned against him.
And so after such treatment, Doflamingo was gentle now, sweet almost - as though he would truly bring Law's suffering to an end. The brat had been fucked so constantly that it was no surprise when he began to respond automatically, hips rolling to take in more, the dark lines of a frown furrowing his brow. He mewled around his gag, head shaking in denial but it didn't stop his body from following after its pleasure.
"I thought you'd already seen how poorly this one behaves to kindness." Vergo gave a hard swat to Law's already rosy flank. It wasn't the first, though the brat did tighten, anticipating more. They'd both had a time of beating Law like a child, until bright tears stood out, unshed, in his eyes while he jerked under their blows, brown flesh turning red.
"Oh, don't be like that," Doflamingo said, settled on his back and simply enjoying the sight of Law helpless and spit upon his cock. He curled a hand over one narrow hip, the bone prominent and fragile. There were bruises popping up there as well; it was impossible to know who'd left them. It didn't matter - Law was going to be so covered, so thoroughly marked by their combined use that anyone who saw him would know. His punishment would be written into his skin for everyone to see; Doflamingo wanted the stink of their come to be the first thing that was noticed. "If it bothers you, you can always have him however you like once I'm finished."
"I'll have him now." Vergo shoved Law forward roughly, still impaled and unable to escape as rough fingers prodded his already-full hole. Law whined and scratched, thrashing with his hips in delicious panic before a thick finger slid in alongside the cock inside him. Doflamingo knew what was to come, adjusting Law as wet tears of disbelief sprung to his eyes. If he didn't think they would go so far, he was a fool.
Vergo didn't spare him more than a few moments before pulling Law's back up against his chest, sliding between the cheeks of his reddened ass. Law made a high, breaking sound as he was forced open, Vergo's cock pushing in alongside Doflamingo's own, making him groan and clench his hands over Law's hips. It took him a long, aching moment inside that gripping heat, Law impossibly full and struggling to breathe.
Vergo was not kind, wasting no time before thrusting forward. The wet slickness inside eased his way but Law still sobbed, trembling. A shame to muffle his sounds now; Doflamingo pulled the gag away and kissed him open-mouthed, swallowing his little helpless hiccups as their powerful thrusts rocked his body. He stroked the brat's cock, hard between their stomachs; Law had been that way nearly from the start, a pleasant counter-argument to whatever he said to the contrary.
"Please, please," Law whined, his voice ruined. It was the first time Doflamingo had heard him beg since they started. "I can't, it's too much - I'll tear. I'll break - "
"Oh, my dear boy, haven't you realized yet?" And Doflamingo couldn't help but laugh, nipping at his jawline and plunging deeper into the impossibly tight grip as Law bore down on them both, abused hole fluttering under the assault. "What do you think the entire point of all this is?"