avengers x male reader (requests are open)

MR. SINISTER

Thunder cracked overhead like the sky itself was tearing open. Rain lashed down upon the ruined outskirts of an old mutant facility—abandoned, decaying, left to rot like the bodies it once held.

But not all was dead.

In the shadows of a shattered control tower, a figure lay face-down in the mud, unmoving. Clothes torn, skin bruised, blood leaking from his temple. Y/N.

A sudden hum of energy pulsed nearby. A swirling crimson portal opened mid-air, sharp and theatrical. Out stepped a tall man in black and red, his cape billowing despite the rain, his eyes glowing with cunning delight.

Mr. Sinister.

He looked around with a scowl. “Savage Land my ass. The coordinates were supposed to bring me to something interesting.” He glanced around the debris. “Instead I get mildew and mediocrity.”

Then he saw it—him.

Y/N.

Unconscious. Bleeding. But alive.

Sinister’s boots splashed through puddles as he approached, the glow of his cape’s collar illuminating the young man’s body. He crouched beside him, lifting his chin delicately with two fingers.

“Hm…”

He turned Y/N’s face, examined the wound, scanned his vitals.

“Mutant,” Sinister murmured. “But not one I catalogued. Curious…”

His fingers hovered near Y/N’s neck as if tempted to snap it—then stopped.

“No… there’s something here. Something special. You’re not dead weight, are you, my sweet little question mark?”

He stood and waved a hand. A swirling field of telekinetic energy surrounded Y/N, lifting him gently from the mud.

“Let’s bring you somewhere… cleaner, shall we?”

Sinister’s Lab – Hours Later

Y/N stirred to the sound of soft humming—almost like opera—but mechanical and cold. He groaned as bright lights stabbed into his eyes.

His wrists were strapped, not harshly, but with precision. He was on a padded surface. Warm. Alive.

And then…

“Ah… welcome back, mystery boy.”

Y/N’s eyes opened wide, darting to the man standing over him. Black lips. Glowing red eyes. A face like carved stone with the arrogance of a god.

“Wh… who—”

“Nathaniel Essex,” he said with a bow. “But most call me Mr. Sinister. It’s more fitting, don’t you think?”

Y/N tried to sit up, but the restraints kept him still.

Sinister chuckled.

“No need for panic. You’re not a prisoner, my dear. Merely… under observation.”

“Observation?”

“You were unconscious in a place that should’ve vaporized you. Your body, your genes, survived a psionic feedback loop no one else did. And yet—no trace of X-gene instability. How very curious.”

Y/N scowled. “So what? You’re experimenting on me?”

“Oh, I would never do anything without consent,” Sinister said with a smirk. “Unless I really wanted to. But you… you’re different. I didn’t touch your DNA. Not yet.”

“Why am I still here?”

“Because, darling,” he purred, “you intrigue me.”

Sinister slowly circled the table, fingers clasped behind his back.

“I’ve studied thousands of mutations—controlled them, bent them, broken them. But you… you absorb power, don’t you? Not like Rogue. No contact needed. You siphon potential. Like an anti-virus of evolution.”

“I didn’t ask for this,” Y/N muttered.

“No one does. But you are this. And the question is… what can you become?”

There was a beat of silence.

Then Y/N muttered, “You could’ve left me to die.”

Sinister paused.

“I could have,” he admitted. “But I didn’t.”

“Why?”

He leaned down, closer, his lips inches from Y/N’s ear.

“Because I liked the look on your face when you slept. So quiet. So fragile. Like something I should break… or protect. I haven’t decided yet.”

Y/N’s breath caught.

Sinister leaned back up, eyes searching his face. “But something in you whispered: Keep me. And I always obey beautiful things when they beg.”

“You’re insane.”

Sinister smiled wide. “Thank you.”

Another pause. The room buzzed faintly with soft tech, scanning Y/N’s vitals.

Then, softer, Y/N asked, “You’re not going to hurt me?”

“Not unless you beg,” he teased—then, more seriously, “No. I want to study you. But I’m not interested in wasting a single cell of your potential. You’re… mine now. Not in chains. In curiosity.”

Y/N swallowed.

There was danger in his presence—an ever-looming threat—but also warmth beneath it, like a fire too close. Sinister’s hands hovered over the restraints.

“May I?” he asked.

Y/N hesitated, then nodded.

The restraints released with a hiss.

He sat up slowly. Sinister stood in front of him, arms crossed, watching.

“I don’t trust you,” Y/N said quietly.

“I’d be insulted if you did.”

“But you saved me.”

“I did.”

“Why?”

Sinister stepped closer, now barely a foot away.

“I don’t save people, Y/N. I collect them. And you… are my most exquisite discovery in years.”

Y/N met his gaze, heartbeat racing. “And what if I refuse to be part of your collection?”

A dark smirk twisted Sinister’s lips.

“Then I’ll simply have to convince you.”

Y/N looked down, then up again.

“…Try.”

Sinister’s eyes lit up.

“Oh… I will.”