I haven't been able to shake the feeling that I should have tacked this on at the end of the last part, so I'm putting it up now.
When A God-Emperor Goes To War
"Doctor?" Rory called out towards the door, "What's taking so long?"
"Sorry about that." The Time Lord reappeared through the door, sans his Fez, "Just making a list of things to take care of next time I'm back this way." He stepped aside, opening the second door to allow his much larger companion to enter, "Rory Williams, I'd like to introduce to you the the immortal Emperor of Mankind, or as I like to call him..."
"General Primus?" Rory blinked, then found himself coming sharply to attention, "It is an honour to see you again, Sir."
"...Bob." The Doctor looked more than a little upset that he had been compliantly upstaged, "You've met?"
"Centurion Ignatius?" The Emperor crossed the control room at what for anyone shorter would have been a run, but with his oversized gait was merely a few footsteps. He passed for a moment, then grasped Rory's hand, "Well me, old friend, well met indeed. If this old fool is dragging me into one of his little games, then it's good to know I'll have a blade I can trust at my back!"
"So you have met." The Doctor added, waiting for the others to take notice of him.
"Met? Ha!" The Emperor threw his head back and laughed loud enough to shake the dust off of the support struts, "He stood beside me, knee deep in the blood and the mud at Tapae, back when I commanded the Legio II Traiana Fortis under Trajan! How in all the Chaos spawned hells did he end up in your debt?"
"That's a very, very long story, which we will have time for later." The Time Lord made his way to the central console, "Right now, all you need to know is that it is his wife and child who have been captured and are being held at Demons Run..."
"WHAT!" the roar of rage that erupted from the Emperor's throat shook the entire T.A.R.D.I.S., and he turned around and stormed back out into the Sanctum Imperialis, "THIS WILL NOT STAND!"
The Adeptus Custodes honour guard, still frozen in place by their locked armour, could only look on in surprise as their Lord and God walked up to their commander and drew the millennia-old power sword from its sheath and inspected the blade. He swung it from side-to-side a few times to get a feel of the weight and balance It seemed to pass inspection, and he nodded his thanks to the startled guard before marching back into the strange blue box. The doors slammed shut behind him, and it faded from sight with a sharp, grinding noise.
There was a click, and the honour guard found their armour was once again under their command, but they now had to explain just what had happened to their charge.
Back in the T.A.R.D.I.S., the Emperor walked over to Rory, holding the power sword out, hilt first.
"Here." He nodded towards the blade, "Bit more of a heft to it than a gladius, although I was always more of a spatha man myself. Still, it's a good blade, and will cut through the toughest armour."
"Thank you." Rory took the blade, the nearly instinctive training he could still remember from a reality that never happened taking over, "It's a find sword."
"Good." The Emperor slapped him on the back hard enough to sending him flying into the central console, "Now then, let's take care of some unfinished business, shall we?"
"What a good idea." The Doctor nodded, "Rory, put that thing down before you have someone eye out."