The halls of Hogwarts whispered with secrets, but none were as carefully guarded as the truth of Harry Potter's allegiance.
No longer the golden boy of Gryffindor, no longer the puppet of Dumbledore, Harry had found a new home in the shadows of Slytherin, under the watchful eye of Tom Riddle.
Tom had adopted him—not in the traditional sense, but in the way that magic itself acknowledged. Blood rituals, arcane sigils, oaths carved into the very fabric of his being. Harry was no longer James and Lily's son alone. He was Riddle's now, and Hogwarts had learned to fear that truth.
But Theo Nott had known it long before anyone else.
He had watched Harry from the moment he stepped into Slytherin House, a small, defiant thing with wild green eyes and untamed magic. Unlike Draco Malfoy, who sought to control Harry, or Pansy Parkinson, who wanted to claim him like a prize, Theo simply wanted.
And when Theo wanted something, he didn't let go.
Year Five – The First Warning
Harry had a habit of drawing trouble, and Theo had a habit of eliminating it before it could reach him.
Theodore Nott wasn't a brute like some of the Slytherins; he wasn't loud like Draco or reckless like Blaise. No, Theo was quiet, methodical, and—most importantly—ruthless when it came to protecting what was his.
And Harry Potter was his.
So when a foolish Gryffindor—a seventh-year who should have known better—cornered Harry in a deserted corridor, Theo was already there, watching from the shadows.
"I don't understand why you're still with them," the Gryffindor sneered. "You're Potter. You're supposed to be with us."
Harry didn't even flinch. "I don't belong to anyone."
Theo smirked from his hiding place. Oh, but you do.
The Gryffindor made a mistake then—he grabbed Harry's wrist.
In the next breath, the boy was on the ground, clutching his throat as invisible claws squeezed. He choked, eyes wide in terror, and turned his gaze toward the end of the corridor, where Theo stepped forward, wand lazily twirling between his fingers.
"If you ever touch him again," Theo said smoothly, his voice a dagger wrapped in silk, "I'll make sure you never touch anything again."
The Gryffindor scrambled away, barely breathing.
Harry turned to Theo, unimpressed. "Really?"
Theo tilted his head. "He put his hands on you."
"I could've handled it."
Theo stepped closer, invading Harry's space the way he always did—silent and consuming. "That's not the point."
Harry sighed but didn't pull away when Theo's fingers brushed against his wrist, rubbing away the phantom touch left behind.
Possession burned in Theo's dark eyes, and Harry—foolish, reckless Harry—let it consume him.
Year Six – Riddle's Protection
Tom Riddle had many rules for Harry.
Some were expected—never show weakness, never trust blindly. But one stood above all: Do not let them take you from me.
So when Riddle found out about Theo's obsessive devotion, about the way he hovered too close, touched too often, and stared too intently, there was a moment where Harry thought Theo might not survive the night.
The confrontation happened in the Chamber of Secrets, the one place where Riddle's power was absolute.
Theo stood his ground, unfazed by the ancient basilisk statues looming around them or the oppressive weight of Tom's magic pressing down.
"He's mine," Theo said simply, as if that were all there was to say.
Tom's lips curled into something sharp and dangerous. "No, Theodore. He is mine."
Harry, caught between them, pinched the bridge of his nose. "I'm not an object."
Neither of them looked at him.
Riddle moved first, stepping forward with that slow, deliberate grace that made lesser men tremble. "Do you think I would allow you to have him?"
Theo didn't blink. "I don't need your permission."
A slow smirk stretched across Riddle's face. "Interesting."
Harry knew that look. It meant Tom had decided something, and whatever it was, there was no undoing it.
"Very well," Tom finally said, waving a hand. "But if you fail to protect him, even once, I will take him back."
Theo met his gaze, unshaken. "I won't fail."
Harry exhaled. "I hate both of you."
Neither seemed concerned.
Year Seven – A Bond Forged in Blood and Magic
It was a war that ended it all. Dumbledore's forces versus Riddle's, light against dark, a battle that tore through Hogwarts like a storm.
And in the center of it all, Harry and Theo stood back to back, spells weaving together in perfect synchronicity.
Theo had killed for him that night.
Harry had bled for Theo.
And when the dust settled, when Dumbledore was gone and Riddle stood victorious, Theo found Harry amidst the ruin and pulled him close, uncaring of the blood, the dirt, the destruction around them.
"You're still mine," Theo murmured against Harry's temple, voice raw.
Harry, exhausted but alive, let himself sink into Theo's arms. "I was never anyone else's."
From the shadows, Tom Riddle watched with knowing eyes, his lips curling in satisfaction.
His heir was safe.
His Harry was home.