The Monster in the Mansion.
It had taken him 30 years to rebuild it. 30 agonizing years of stealing, lying and killing to rebuild it, but finally, the "Immortality Gate" as the foolish ape, Naismith had called it, was fully repaired. The Nuclear Vault had been the most difficult and dangerous to repair, thankfully his Time Lord body was able to withstand far more Rads than a human could, even if it had protection. He stole depleted uranium from U.N.I.T, and using some very advanced methods that humans wouldn't discover for a few millennia, turned into reactor-grade uranium. He typed into the computer the instructions. He would continue with his original plan, to turn the Earth into a warship. "P-Power-up initi-initiated, approximately th-thirty one hours until complete recharge is a-achieved." The computer stuttered, it had been switched off for 31 years, the hard drive was partially corrupted. 31 hours was a long time, but he couldn't risk blowing a circuit. He wandered around the house, bored. He had waited so long for this moment, to finally achieve his ambition. The drumming had stopped after he came back, but his mind was too far gone to return to any form of sanity. He eventually fell asleep, lost in thoughts about universal domination. He woke up and checked the computer. 17 hours to go. The Gate was starting to come to life, slowly but surely. "I'm so close..." He whispered to himself. Nobody ever came to the Mansion, they said it was "haunted". Stupid apes, why The Doctor liked them he had no idea. It made him feel sick to be around them, they were little more than animals compared to him. "Disgusting creatures..."
His mind was made up. He would accelerate the process, he wanted this planet and he wanted it now. He turned off the fusebox and turned the Generator to maximum. Within the hour the Gate was fully charged. He stepped into the glowing sphere which then turned into a forcefield. "Initiating t-template replication." The Gate began to hum, it was at 76% before the event that would change his life forever would occur. Sparks shot out of the machine, a warning alarm blared. "Energy Regulation Circuits have fused. Critical Power Surge imminent." "WHAT!" The insane Time Lord screamed, then he remembered. He accelerated it, it was his fault that this had happened. "ABORT PROCESS!" He screamed, desperate. "Unable to comply, shutdown controls have failed. 30 seconds to Gate destruction." came the cold clinical reply. "SHIT!" He banged his fists on the forcefield, desperate to try and break free before the power surge hit. He saw the cables fry and explode, the computer and the monitor blew up in a shower of metal and silicon. Finally, the surge hit the gate which immediately blew apart, pieces of metal and circuitry used into flesh and bone, unable to hear the screams of the Time Lord as his body was borderline ripped apart. He lay on the ground, swollen, deformed and bleeding and he just screamed as his nerves felt like they were on fire. His back suddenly felt very odd, as if something was trying to break out of it. The skin ripped open, and he saw a naked version of himself, just before the accident, crawl infront of him. "Mother?" it asked telepathically. The mutated monster replied. "Hungry..." The naked Time Lord nodded and brought it's mutated mother a can of beans, which it fed to... him. Within an hour, another Master was born. It's older brother taught it everything it's mother had. As his two children talked, the original began to think, to formulate a new plan. He would make the Doctor pay for everything he had suffered. He would re-populate this world with copies of himself! Earth would become New Gallifrey. He spoke, but his voicebox was too badly damaged for either of his clones to understand him. If they could, they would have heard "Doctor, you'll suffer for the pain you cause!"