For the first time in his life, Harry didn't have to stand alone.
The realization settled into his bones like a warm fire on a cold night. The weight on his shoulders, one he had carried for as long as he could remember, didn't vanish, but it shifted. The burden was still there, but it was no longer his alone to carry.
His father was here.
Tony Stark was here.
And he wasn't leaving.
Tony clapped his hands together, breaking the silence. "Alright, kid. Time for some science."
Harry blinked. "Science?"
"Yeah, science," Tony said, rolling his eyes. "I know you magic folk like to wave sticks and say funny words, but glowing eyes? That's new territory, even for magic. So, what do we do when we encounter something we don't understand?"
Harry smirked. "Blow it up?"
Tony pointed at him. "That's my boy. But no, in this case, we study it. Experiment. Test some theories. So, first question—when did this start?"
Harry thought for a moment. "Honestly? Right after I read your letter. My magic's always been strong, but the moment I felt—really felt—that I had a father, it flared up."
Tony hummed thoughtfully, pacing the room. "Interesting. So we can rule out it being some random genetic mutation. This is magic-related, emotional, and new. If it were some wizard puberty thing, it would've shown up years ago, yeah?"
"Probably." Harry frowned, glancing at his hands. He flexed his fingers, and green energy flickered briefly before fading.
Tony whistled low. "Okay, that was cool as hell. Do that again."
Harry narrowed his eyes and focused. His magic responded instantly, rushing to the surface like a living thing. His fingertips glowed faintly, an emerald hue seeping from his skin like mist. It felt effortless, natural—more than casting spells ever had.
Tony let out a low whistle. "Kid, that is some next-level energy manipulation."
Harry raised an eyebrow. "What, like magic?"
Tony shook his head. "No, not like magic. Like something else. Magic is usually external—you channel it through a wand, through words, through rituals. But this?" He gestured at Harry's hands. "This is coming from you. It's more like…" He hesitated.
"Like what?" Harry pressed.
Tony exhaled. "Like an Arc Reactor."
Harry frowned. "I don't know what that is."
"Right, right. You're still catching up on the non-magical world. Okay, short version: an Arc Reactor is a high-powered energy core. I built one into my chest to keep shrapnel from punching a hole through my heart. It also powered my first Iron Man suit."
Harry's gaze flickered to Tony's chest. "You had a piece of metal in your heart?"
"Had. Past tense. Long story, we'll get to it. Point is, the Arc Reactor generates energy from within, just like you seem to be doing."
Harry considered that. He had always assumed magic came from within, but wizards typically used wands or words to channel it. This, however, was different. His magic wasn't just responding—it was manifesting.
"You think my magic's evolving?" he asked.
Tony smirked. "Kid, if you're anything like me, you're not evolving. You're upgrading."
Harry snorted. "Right, because I needed more power."
"Hey, I'm not complaining. If my son is basically a wizard-powered nuclear battery, I'm so putting that on a T-shirt."
Harry rolled his eyes, but he couldn't help the small smile that tugged at his lips.
Then something shifted in Tony's expression. The humor remained, but beneath it was something more serious.
"Listen, kid," Tony said, stepping forward. "I know we're having fun with the whole 'glowing eyes' thing, but I want to make something clear—this? This doesn't scare me."
Harry's breath hitched.
Tony's voice was firm. "You could start levitating or shooting laser beams out of your hands, and I'd still be here. No running. No second thoughts."
Harry clenched his fists, his magic pulsing in response to the emotions welling inside him. "You mean that?"
Tony met his gaze without hesitation. "Damn right I do."
Harry swallowed hard. He had spent so long being feared—by the Dursleys, by the wizarding world, by Voldemort. Even after the war, people still looked at him like he was some untouchable legend.
But Tony?
Tony looked at him like he was just Harry.
Not a savior. Not a soldier.
Just his son.
Harry exhaled slowly, letting his magic settle. The glow in his eyes dimmed slightly, though it didn't fade completely. "Alright," he said finally. "Let's figure this out."
Tony grinned. "Now that's what I like to hear."
Two hours later, Tony had set up a makeshift lab in Grimmauld Place's drawing room. Several Stark Tech scanners hovered around Harry, beeping softly as they analyzed his energy output.
"This is ridiculous," Harry muttered, watching as Tony typed furiously on a holographic keyboard.
Tony didn't look up. "Science is never ridiculous."
"Says the man who built a flying suit of armor in a cave."
Tony grinned. "Damn right."
Harry rolled his eyes but stayed still as another scanner passed over his face. His magic stirred again, responding to the analysis, and the readings on Tony's screen spiked.
Tony whistled. "Kid, you're off the charts. You're radiating power like a miniature reactor."
"Is that bad?"
"No idea, but it's awesome."
Harry groaned. "Fantastic. I'm officially a science experiment."
Tony smirked. "Welcome to the family, kid."
Harry was about to retort when the room suddenly shook.
Both of them froze.
A second later, the ancient walls of Grimmauld Place shuddered, magic crackling along the floorboards. Harry's instincts flared, and his glowing eyes snapped toward the source of the disturbance—
The front door.
Something—or someone—was on the other side.
Tony's expression turned serious. "Friend of yours?"
Harry stood, his magic thrumming in warning. "Not likely."
The door rattled again, harder this time.
Harry flexed his fingers, green energy sparking at his fingertips. Whoever was on the other side had no idea what they were walking into.
Tony stepped beside him, a cocky smirk forming on his lips. "Alright, kid. Time to see what you can really do."
Harry's emerald eyes flared, magic coiling around him like a living storm.
"Let's find out."