James had called Regulus Bambi for as long as he could remember. It had started in third year, a teasing nickname he threw around as if it were the most natural thing in the world.
"You do realize Bambi was a deer, right?" Regulus had muttered one evening in the library, nose buried in a book, as James slouched in the chair across from him, idly flipping through a Quidditch magazine.
James had only grinned, twirling his quill between his fingers. "Doesn't matter. You're still my Bambi."
Regulus had rolled his eyes, letting out a soft exhale through his nose. He never questioned it further, just assumed it was another one of James’s ridiculous nicknames, like the way he called Sirius Padfoot before anyone else or the way Remus became Moony. James had a habit of naming things, of claiming them as his own, whether they knew it or not. But now Regulus has claimed the Gryffindor's heart.
The nickname stuck, slipping into conversations effortlessly, private or public. In the common rooms when they were left alone in rare moments of peace. In the hallways between classes when James would nudge his shoulder and smirk. In hushed whispers under the cover of darkness, when James pulled him close in secret corners of the castle, away from prying eyes.
Regulus never admitted how much he liked it.
He never stopped to think about why James had chosen it—until their sixth year.
Until the night James showed him what he truly was.
---
It was a cold winter evening, the sky dark and clear, the Forbidden Forest stretching before them like a silent, waiting thing. The Marauders had dragged Regulus into one of their late-night escapades, under the guise of “giving the poor little Slytherin some fun,” as Sirius had so eloquently put it.
He had scoffed, insulted by the idea that he couldn’t have fun without them, but he had followed anyway. He always did.
Regulus didn’t know why he let James talk him into things. Didn’t know why he let himself be pulled into James’s world so easily, so effortlessly, as if he had never belonged anywhere else. He told himself it was for the challenge, the back-and-forth of it all. The way James was infuriatingly persistent, a force of nature that demanded attention, affection—everything.
But if Regulus were honest with himself, he would have admitted that it was simply because he liked it.
And then James had shifted.
Regulus had known about the Animagus transformations—everyone with half a brain suspected something was off about the Marauders—but seeing it happen was entirely different.
Where James had stood just moments ago, there was now a stag. Tall, regal, breathtaking in the moonlight, its coat a deep, rich brown that looked almost golden under the stars.
Regulus had gone utterly still.
James took a cautious step forward, the sound of hooves barely audible against the forest floor. The others were laughing, talking, but it all faded into the background as Regulus met the stag’s gaze.
Warm hazel eyes stared back at him.
James’s eyes.
Something inside Regulus clenched tight, like a fist around his heart.
James was a stag.
And Regulus…
He swallowed hard, his breath catching as memories flickered through his mind—James calling him Bambi in that teasing tone, always with a soft edge to it, always looking at him like he was something delicate and untouchable.
Like James had known before he did.
Regulus had never figured out his Animagus form. He had never cared to try. But in that moment, he knew. He felt it in his bones, in the way James looked at him like he was something precious, something that belonged to him.
His doe.
His Bambi.
Regulus sucked in a sharp breath and turned away, pretending his hands weren’t shaking. "You’re ridiculous," he muttered, pushing past Sirius and Remus, heading back toward the castle without another word.
James shifted back with a soft rustle of magic, watching him go.
"My Bambi."
Sirius smacked him on back of the head. "Stop trying to court my baby brother!"
James grinned at him. "Like you courted our dear wolfie there?"
Sirius did not dignify a rensponse but James noticed how Remus looked away and how Sirius held back a smile.
---
That night, Regulus found himself tangled in James’s bed in the Gryffindor dorms, pressed close in the dark. They weren’t supposed to be here—not together, not like this, not so late in night—but the rules had never mattered much when it came to James.
James was always too warm, always throwing off heat like the sun itself. Regulus, who had always been a little cold, a little distant, found himself seeking it out more often than not.
"Is that why you call me Bambi?" he asked quietly, his voice barely more than a whisper.
James hummed sleepily, his breath warm against Regulus’s temple. "You’re my doe, love," he murmured, words thick with drowsy affection. "Always have been."
Regulus traced slow, absentminded circles on James’s bare shoulder, his thoughts distant. "That’s idiotic," he muttered, but there was no real bite to it.
James let out a lazy chuckle, shifting to pull Regulus closer, one arm draping over his waist. "Yeah? But you like it."
Regulus didn’t answer.
Because in James’s arms, safe and warm, he thought maybe—just maybe—James had been right all along.