Work Text:
It was over, Voldemort had fled the Department of Mysteries, leaving his followers behind.
Harry made to move away from the safety of the statue, freezing in confusion when Dumbledore yelled out, "stay where you are, Harry!"
The fear in his voice had him furrowing his brows in confusion, the hall was empty, barring themselves, Bellatrix, and the now baby Fawkes.
And then, without warning, his mind was burning, flames building around him, an unknown creature trying to wrap around him, trying to take him over, trying to end him.
Child.
It was Him, He was here, as He always was, and Harry felt himself relax just a little.
Child, you need to let me take control.
Without hesitating, he let himself fall back, as another presence filled his mind.
"Get out!" He cried, grasping their head, and pushing with His entire mind, throwing the invading being out.
Harry let himself drift off, let himself sleep, knowing that He would keep them safe.
He always did.
A dark smoke left their body, flowing rapidly from their mouth, it quickly solidified into the form of Voldemort, and He quickly grabbed their wand, pointing it at the man, who looked at Him in both fear and fascination.
"How did you remove me?" he demanded, dodging a spell flung at him from Dumbledore.
He grinned sharply, "human minds are rather simple to expel from a mind like mine."
"You're saying that you're not human, Potter?"
"Oh no, Harry is, or was, human," He paused, bringing their wand up to scratch at their head, "well, he's human in body, at least."
Some Aurors finally decided that now would be a good time to flood the hall, and Voldemort quickly fled, this time without sticking around to attempt a possession.
He dropped their hand, pocketing their wand, ignoring the way that Dumbledore looked at Him.
An hour later and all three of them, or well, two that were visible, were sat in Dumbledore's office.
"So," Dumbledore began, staring at them like a hawk, "who are you and what have you done with Harry?"
They both frowned, but He began to speak, "I am called the Master," he started, before pouting at him, "and I haven't done anything to Harry, he's here and aware."
Dumbledore blinked, "but possession leaves the other person unaware of their actions."
He scowled, "yes, well normally possessions aren't consensual."
"You're telling me that Harry let you possess him."
"I did," Harry interjected, sulkily.
"Why? Don't you know he could be You-Know-Who?" he asked, barely concealed panic laced his voice, which set the Master off.
"You knew he had that little bit of soul in him!" he accused, and Harry gaped, their conflicting emotions clashing on their face.
"He knew?"
"Well obviously, if that panic is anything to go by."
"I thought you got rid of it?"
"I did get rid of it when you gave me permission to be here, Harry, it was unwanted and causing you pain."
Harry relaxed at that, but the Master was still tense, their gaze returned to Dumbledore, who was looking at them with a horrified yet intrigued look on his face.
The Master sighed, "look, I don't take over this body, unless I've gotten permission to do so or ask and he lets me, Harry's time here at this Rassilon damned school is his own," he huffed, "and I do not hold ill will towards Harry."
Dumbledore narrowed his eyes at what he wasn't saying, "and the other students?"
"I will admit that I do hold some ill will towards the students, particularly the ones that keep going out of their way to harm Harry, but I'm unable to act on them, after all, this is Harry's body, he can take control back any time."
"You mentioned he wasn't human anymore, at least in mind?"
"He's spent over a decade with me in here," he pointed at their head, "mentally, he is far closer to my species."
"And what species would that be?"
He grinned, knowing that the magical world had no record of him or the Doctor, thanks to their refusal to be involved with any of the muggle alien departments, still believing them to not exist, "Time Lords."
As he'd predicted, Dumbledore just looked at him in confusion, "I've never heard of them."
"We're very," he thought back to their population count and frowned slightly, "rare."
Dumbledore nodded slightly, still looking at them warily.
"Is that all professor?" Harry asked, "can we go? I'm tired and I have classes tomorrow."
He narrowed his eyes but nodded, and they got up to leave.
Once they were at the door, Dumbledore called out, "oh, and Harry... and 'Master'," he looked at them over his glasses, "I will be keeping an eye on 'both' of you, if one toe steps out of line," he trailed off, and the Master snorted.
"Got it."
With that, they slipped out of the office, shutting the door quietly behind them.
They walked down the staircase and into the quiet hall, a smirk gracing their face as they made their way back to the tower.
They could feel a tiny part of their mind clash and meld together, possession was one way to put it, they supposed.
After eleven years together, their minds had started blending together, leaving them with a bond similar to that of the Weasley twins.
So, when the Master got his body back, he'd be taking Harry with him.
He was, after all, the closest thing to a little brother that he had now.
A little DNA alteration and he would be.
But for now, it was just Harry and his spirit tag-a-long, the Master.