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Zero Sum

Chapter Text

The time came when it was necessary to transfer the paradox machine to its permanent home. As powerful as the TARDIS was, it paled in comparison to the Eye of Harmony, the black hole housed at the very heart of New Gallifrey's central city. Through the Master's unending conquests, the Time Lords now had the technology for the machine to be separated from the ship, and the Master was greatly looking forward to having a functioning TARDIS again. It was a waste of resources to let it sit there collecting dust in a vault.

The Doctor, when he'd been told the news, hadn't been quite so thrilled. He'd retreated to his lab and buried himself in work. The Master could feel him brooding all the way from the Great Tower.

He didn't have the patience for the Doctor's moods, not when he had incredibly complex temporal-gravitational calculations to sort out. No one had ever moved a paradox machine before, at least not without collapsing the paradox. And he was not about to lose his empire because of a calculation error. He called Allia. "Go talk to your father," he told her. "He's in a sulk."

She sighed. "You always make me do the dirty work," she said, with reluctant affection.

"That's right," the Master said, unrepentant. "All you have to do is go over there and smile nicely and he'll go back to being nauseatingly mushy."

"Why don't you just zap him?" she asked. That was her term for the way he used their Archangel link. He could hear the Doctor's thoughts from galaxies away, and send him pain or pleasure with equal ease. But sometimes a subtler weapon was necessary.

"Because I'm too busy to micromanage," the Master told her. "Do you want your own plasma squad or not? Because I could give it to one of my other lieutenants."

"Fine, fine," she said, relenting. "But I want the squad and a cruiser. I do have a rebellion to crush next week."

"That's my girl," the Master said.

"Allia!" said the Doctor, spreading his arms wide for a hug. He squeezed her tight. "Feels like you've been gone forever."

"It's been two months," she reminded him. "I had a break, thought I'd drop by."

"I'm glad," said the Doctor, the corners of his eyes wrinkling as he smiled dotingly.

Mushy indeed, she thought. Oh, well. She didn't mind, not really.

"You're in charge of the Traidus cluster now, aren't you?" he asked, already heading for the kettle. He always made tea when she visited.

"Yes," she said, settling into a chair at the kitchen table. "It's going well. There's some trouble on Rho-4, but I don't expect it to be a problem."

The Doctor frowned as he set out two teacups. "Trouble?"

"Rebels," she said. "The usual troublemakers. There's always a group of them who aren't affected by Archangel."

"It's my fault, I suppose. I could never reach better than 99% effectiveness," the Doctor said, regretfully.

"Don't feel sorry for them," she told him, not for the first time. "Some people don't know what's good for them."

"One percent of the universe is a lot of lives," the Doctor said. "I just wish..." He trailed off, shrugged. They'd had this discussion before, and there was nothing new to add.

"You don't really want the whole universe to be peacefully controlled," she told him. "How boring would that be?"

The Doctor gave her that despairing look of his. "You're too much like him, sometimes."

"He says the same thing. I'm too much like you, too soft." Sometimes she wished her two fathers would stop trying to mold her in their respective images.

"I'll have to take half the blame, then," the Doctor said, quirking a smile. The kettle whistled, and he turned it off. "He sent you, didn't he?"

"Can't fool you," she said.

He poured their tea, quiet as he went through the familiar ritual. When he added a plate of chocolate biscuits, she knew something was bothering him. That was his comfort food.

"Want to talk about it?" she asked, after he'd been staring into his tea for several minutes.

"Not really," he said. "But he's not going to stop pestering you until I do, so..." He sipped his tea. "Best get on with it."

"Are you two having trouble again?" she asked.

"No no," the Doctor insisted. He gave a soft smile. "I don't see enough of him, that's all. Ruling the universe takes up most of his time. We have the link, but it's not the same."

"You could offer to help," she said. "You're probably the only one he trusts enough to shoulder the important stuff."

The Doctor gave a laugh. "Nah. I'm too soft, remember?"

"You've designed half the armoury," she pointed out.

He didn't look entirely comfortable about that. "I also want the universe to be peacefully controlled, rather than massacred. We never could agree on that, so we compromised."

"We're their superiors," she said, confidently. "They deserve whatever we give them."

"Oh, Allia," he sighed, sadly. After a pause, he continued. "It's the TARDIS. She's being restored, in preparation for the transfer."

"Didn't that used to be your ship?" she asked. He'd rarely talked about it, but it was a point of general knowledge. Everyone knew that the Empire was founded on the paradox locked inside the blue box.

"A long time ago," he said. "I said goodbye to her, so I could keep you." He looked up at her, and his eyes were so old. He still looked the same as ever, physically young, which made it hard to remember that he was over a thousand years old. She was just coming up on her first hundred, and even though she was older than almost everyone else on New Gallifrey, it was humbling to realize how young she actually was.

"Well, speaking for myself, I'm glad you did," she said, lightly.

"I tried to forget about her," he continued, staring down at his tea again. "Did forget, for decades. I've forgotten more than you've even lived."

"You remember," she said. "You used to tell me all those stories about your adventures."

"Only the parts that didn't hurt," he said, then sighed. "They used to say that once you hit the thousands you'd spend more time with memories than the present."

"The old Time Lords?"

"Yes," he said. "I don't like my memories. Sometimes I've thought..."

"What?" she asked.

"I've thought about asking him to put the rest of them away. Everything but our lives here." He looked up at her again. "I don't want to live in my memories. I want what I have now. You and him, and your brothers."

"So don't live in your memories," she said. It seemed simple enough to her.

"I'm trying, but the TARDIS, it's... that's almost my entire life. My ship." He looked pained. "I wish they'd just left it in that vault."

The Master heard everything, of course. He was used to the constant buzz of the Doctor's thoughts, relied on the link to keep an eye on him and influence him when necessary. He'd never quite been able to bring the Doctor completely over to his point of view--there was some core of do-gooding that was impossible to pry loose without risking his whole personality. The Master had considered a straightforward wipe when the Doctor had been particularly irritating, but in the end he'd decided a little conflict kept things interesting. He liked it when things were interesting.

The fact that the Doctor missed him was rather pleasing for his ego. Even with the universe under his leather-gloved thumb, his domination of the Doctor was so much more satisfyingly personal. The man who'd thwarted him for a thousand years, now safely at his side, his genius (however inferior to the Master's) turned for the benefit of the Master's conquest. The sex was good, too. Perhaps he would pay a visit to the house, later. A good hard fuck still quieted the Doctor's mind better than any zap.

He set aside his calculations to check on the reports flowing in from every corner of his Empire. Things were going so very well. Even the rebellions were satisfying, giving him the chance for a spot of slaughter and the occasional genocide. He always made sure to lead the most promisingly deadly campaigns himself. He liked the personal touch, and besides, it was good for his image. Terrified respect was so useful.

Life was, in other words, almost entirely perfect. But that didn't mean he should let himself get sloppy.

The paradox machine was a problem. He'd cobbled it together using one ancient Type-40 and whatever Earth technology he'd been able to find that was crudely advanced enough to be useful for more than a paperweight. It had been running for a hundred years now, but he needed it to run for a hundred trillion more. That meant stability, that meant power. That meant somehow transferring the linchpin of the universe to the thickly-armoured bunker below the city, upgrading it, and connecting it up to the Eye of Harmony.

Even aside from the technical problems, it was just the kind of moment that people tended to take advantage of. He loathed vulnerability, especially his own, and until this was all over everything was at risk. Everything.

He read the next report, and frowned. Their little pest problem was back, again. The first thing he was going to do once he had a working TARDIS was go back in time and destroy the Cult of Skaro personally. The Daleks had to be the most obstinately annoying race in the universe, and he was sick of them popping up at the fringes, manipulating a species into helping create more Daleks, and then buggering off once the Master's fleet started blowing them out of the sky. There was only room for one ruler of everything, and that was not going to be some disgusting mutant blob in a personal tank.

He slapped down the report and glowered. He needed to make something die. He took the lift down to the torture rooms, and tried to decide which miserable piece of shit to put out of his misery. Oh yes, he knew which one.

He walked over to what used to be Jack's cell. Now it held the imbecile who'd let him escape. The Master had been slowly flaying him for almost a decade now, always letting him heal before the next round. He was an almost unrecognizable mess of scar tissue now, and there'd been a satisfying rattle in his breathing during their last round. Best to make sure he dies screaming rather than peacefully in his sleep.

Losing his favourite (well, second favourite) victim and pincushion had made him very, very angry. Decades of torture had probably left the Freak too broken to do more than huddle in the basement of his rescuers, but he still didn't like it. He had a sense for knowing when someone was up to something, for seeing the shape of a plan, and there were too many things falling into place. It made him very, very angry.

If he was going to visit the Doctor later, he needed to be able to pretend to be vaguely nice, and that meant someone else was not going to survive the next few hours.

"Two visitors in one day," the Doctor said, wryly. "You just missed her, as you well know."

"Busy day at the office," the Master said, giving him a kiss. "I hear you've been missing me."

The Doctor's expression softened. "It was sweet of you to send her. Though if you hadn't posted her so far away..."

"She goes where she's needed. You know how it works." He closed the door behind them and pressed the Doctor up against the wall. "I'm not here to talk about her." He rubbed his hand over the Doctor's crotch, and gave him a zap of pleasure, just to get things started.

The Doctor moaned. "You're not here to talk at all," he said, already starting to glaze over. He was so delightfully receptive, but then, the Master had made him that way. His very own customized Doctor. Most of the work had been done in the initial stages, but he still found time to tweak things here and there. A memory clarified or hidden, a bit of internal chemistry altered just a notch. The link made behavioural conditioning so easy, and the latest spinal implant gave him even finer control than the one before. No matter how stubborn the Doctor's ingrained morality might be, there were still so many other things that could be altered at the slightest whim.

The remote control wasn't a clunky device anymore. He just needed to think, and the Doctor's body obeyed. The Doctor made a choked sound as the Master paralyzed him, and amplified his surface nerves.

"Trouble breathing?" he asked, slipping his hand under the Doctor's shirt, feeling the complete failure of his chest to rise and fall. There was always such delicious panic in the Doctor's eyes when he did this. It made him want to do it more. Sometimes he waited until the Doctor had almost passed out, and savoured his fear before releasing his lungs. That first, desperate gasp was like music to him.

He only waited a few minutes before letting him breathe again, this time. Oxygen deprivation always made the Doctor pliably euphoric, and grateful for every breath. As he should be.

"Something different today, I think," he murmured, slowly unbuttoning the Doctor's clothes. He leaned in and gave his neck a hard nip, and felt the Doctor yelp in his head, even though he couldn't so much as twitch. He considered his options, and inspiration came.

"You wanted to see me so much," he continued, tracing his fingers around the Doctor's eyes. "Let's make you want a little more." He released the Doctor's paralysis, and at the same time disabled his optic nerves. The Doctor immediately reached out for him, anxious and aroused, and the Master let him touch.

"Bastard," the Doctor muttered. His hearts were racing.

"Try again," the Master said, a hint of steel in his voice that he knew made the Doctor quiver in the best way.

"Master," the Doctor breathed, and then groaned as the Master's hand wrapped around his cock.

It wasn't until a long time later, when they were both exhausted and sated, that the Master turned his eyes back on. The Doctor blinked and rubbed his eyes, and drank in the sight of the Master like a man dying of thirst. Oh yes, he'd have to do this one more often.

"Miss me?" the Master said, smugly.

"Terribly," the Doctor said. He stared intensely at the Master's face, then down at his body as his hands wandered along the Master's chest. "I've been considering your offer. I'd miss the house, but I miss you more."

"You'll have an even better lab," the Master told him. "A whole floor, the latest equipment." He reached down and grabbed the Doctor's arse. "You can come over for lunch and suck my cock."

The Doctor moaned, and his irises dilated. "I miss having you in my head. Properly, I mean."

"The link's not the same," the Master agreed, echoing the Doctor's earlier sentiment. He released the Doctor's arse and pressed his palm against his face. Slipping inside the Doctor's head was still an exquisite trespass, even after a century. Eleven hundred years of memories that were as familiar to him as his own, he'd handled them so many times. So much raw material to play with. "I'll be able to watch you dream again," he said.

"Yes," the Doctor said, happily. The Master could see him already planning what to pack. It was so sweet, how much the Doctor needed him. So conveniently useful. That had been there from the start, without any manipulation at all.

He pulled up a memory from their time on the Valiant and polished it like a jewel. It had been some of the best months of his life, when he'd been whittling away at the Doctor from every angle, when he'd had his hands red with the Doctor's blood on a regular basis. He was certain he could come up with an excuse for another surgery. The Doctor clung to this body despite how it had been weakened by carrying Allia, which meant he still needed, or at least thought he needed, regular checkups, the occasional injection. There'd even been some extremely entertaining implants for a few decades, though right now the Doctor's body was sadly untampered with. Once the paradox machine was safely in its permanent home, that would have to change.

Oh yes. He had so many ideas to try. Some of them were going to hurt quite a lot, he imagined. He couldn't wait to see the Doctor writhe.

The Doctor was oblivious to his plans. The Master liked it that way. Once he was living in the Great Tower, the Master would need to be more careful about keeping the wrong information from reaching him. It was easy when the Doctor kept to the house--he'd never quite fit in with the new Time Lord society, which wasn't much of a surprise, and isolation kept him needy. Especially now that all their children had left the nest. It was time to reel the Doctor back in.

"Do you want me to help you pack?" he asked.

"You're sure you're not too busy?"

"I can spare a morning," the Master said. "Allia can help. Call it family time."

The Doctor's happiness was so strong he had to dampen the link for a few seconds.

The Doctor's relationships with his sons had never been quite as warm as the one he had with his daughter. Chalk it up to her being the first, blame it on them being loomed into infancy rather than born. Or maybe the Master hadn't kept the balance so fifty-fifty as he had with Allia. The Doctor had always suspected as much, but no matter what the ratio, they were still his children, and he loved them.

Their youngest, Kerinoxacavilli, was still in the Academy. Not that it was the Academy of the Doctor's youth, given that the professors were all adult-loomed from the Master's DNA, and there weren't enough students in the upper classes for houses. In a few generations it would look more like it was supposed to, he expected.

Kerin had left home early, partly because he was ready for the challenge, but also because he'd spent so much time picking arguments with the Doctor and making sarcastic remarks. It had been like living with a teenaged Master, and the Doctor wasn't young enough to enjoy that particular experience all over again. Now that he'd passed the half-century mark, the Doctor was hoping their relationship would improve. And if it didn't, well, there was no harm in trying.

He left the Great Tower and walked to the Academic Residence quarter. He took his time strolling through the city, seeing how life had settled in since he'd last visited. For all that he'd helped with planning the city and creating its inhabitants, it had never really felt like home. That was reserved for their house at the edge of the dome. He would miss it, but it was too empty without the children, and he'd rattled around on his own there for too long. The change would do him good.

His status as a Founder gave him access to almost anything in the city. It also gave him a lot of attention. He was a rare enough sight that people stared at him in the streets, pointing and whispering, so he was glad to reach the residences and make his way inside. He'd never been much for celebrity.

He found Kerin's door and knocked.

"Oh, hello father," Kerin said, in that wary way of children when their parents made a surprise visit.

"Don't I get a hug?" the Doctor asked, holding out his arms. Kerin rolled his eyes, but obliged with a curt embrace. ”Oh, it's good to see you."

"What are you doing in the city?" Kerin asked, letting him into the room. "I thought you hated it here."

"I never hated it," the Doctor protested. "I've moved in with your father, in the Great Tower. Thought I'd give the city another try."

"You should've called first," Kerin said, gathering up some papers. "I have to go to class."

"Which one?" The Doctor started nosing through a stack of books, noting the various titles.

"Independent study," Kerin said, making a face at the Doctor's prying. "There's a group of us helping with the paradox transfer."

The Doctor stilled, then covered his discomfort with a smile. "You were always so smart," he said, proudly. "That's a big responsibility."

"Yeah, I know," Kerin said, rolling his eyes again. Still as prickly as ever, it seemed.

"Think they'd mind your old dad paying a visit?" the Doctor asked, eyebrows raised in hope. "I promise not to be too terribly embarrassing."

"Don't make promises you can't keep," Kerin said, then sighed. "Fine, you can come."

"Great!" said the Doctor, giving Kerin a slap on the back. "This'll be grand."