Peter cried out, each breath coming in a tearful shudder. “Mr. Stark? Mr. Stark, please.”
He clutched his stomach, his body quivering with each wave of pain. His limbs were being ripped apart; something was taking his body apart piece by piece and he could feel it, he could do nothing but feel. Peter choked as he stepped forward, his legs giving out underneath him. Suddenly, everything was too bright and too loud. “Mr. Stark, I don’t feel so good,” Peter mumbled.
“Kid? Oh god, kid,” Mr. Stark breathed, dread colouring his tone.
Peter’s pain heightened, his nerves shattering and his bones cracking. He shuddered, a searing inferno extending from his eyes to his legs, everywhere was agony. His muscles liquefied then hardened, spasming from every miniscule movement. Ice crystallized every cell in his body and he let out a sob. An echo of a plea fell from his quivering lips. Please.
Tears were flowing down his face, caressing his cheeks in a pseudo-comforting manner. “I-” his throat was closing, words unable to make it past his unease. “I don’t know what’s happening.”
Peter collapsed into Tony’s arms, the contact making him feverish. He cried out but struggled little because each movement caused his muscles to spasm, his body to shake. His torment shifted from a burning fire to bitter cold. Peter was fading and he was so, so scared. Tony held him close, whispering. Telling him it was going to be okay. He was going to go back home, tell Aunt May how awesome space is, wasn’t he?
“I don’t want to go,” he whimpered. “I don’t want to go.” There was light everywhere, overwhelmingly bright. It terrified him so much he gasped, stealing the air from around him faster than his lungs could take it in. He clutched Tony even tighter, begging anyone who was listening to help. He grasped his mentor tight, feeling Tony’s bones crack under his hands.
“Sir, please. Please-” he burned, heat destroying him and he wailed. “I don’t want to go."
His senses faded, falling away one by one until Peter couldn’t feel anything besides his torture. He was floating in despair and fear and he knew it would never stop, not until he died. He tried to focus on Mr. Stark’s face but it blurred together until he too was nothing but a glow. He looked into the radiance of death, the devastating certainty of the light. Peter was crumbling. He felt Tony’s tears dripping down his face, mixing with his own and his heart ached.
“I’m sorry.” He whispered. His legs were gone first, disintegrating into the air. His muscles withered and his cells died, his body shattering as he lay there. The fire sizzled out, leaving him frigid and still. Everything ebbed until he could grasp at one last thought. Mr. Stark, I’m sorry I wasn’t better.
-----------
Tony shook, his hands trembling as he grasped at the dust Peter had left behind. He scrambled to hold onto something firm and solid. He couldn’t think, couldn’t focus on anything beyond the fact that Peter had just died in his arms. Peter, his kid. Tony knew he was crying, his cheeks were wet, yet he didn’t feel it. He felt nothing.
“Why did you do that?” Tony asked, his voice hoarse and barely scraping past his throat. He watched Strange blankly, a million thoughts and none at all racing through his head.
“There was no other way.” Strange murmured, disintegrating right before his eyes and fading into the air. He couldn’t muster up the energy to care, Strange’s answer barely registering in his mind.
Tony turned his eyes back to what was left of Peter. He was empty. Peter took all of his anger and fear with him, leaving him drained. His muscles ached with the pain of the fight, but his heart hurt more. He promised to return Peter home, he had sworn.
Tony collected the dust in his palm, mindlessly watching it sift through his fingers and flutter to the ground, wind sometimes seizing it for the skies. His shoulders sagged; he was exhausted to the bone. Tony raised his head toward the sky and hated. He hated Strange for giving up the infinity stone to Thanos so easily. He knew Thanos would’ve gotten it eventually - and Peter still would have died - but he didn’t care. He recalled Strange saying he would never trade his and Peter’s lives for the stone and a new wave of misery suffocated him.
He despised Thanos, for causing so much pain and enjoying it. He remembered the look in his glowing eyes. The glee at the sight of Tony defeated and on the ground below him. He stole Peter from him and Tony vowed vengeance.
A hand rested on his shoulder and he glanced over. Nebula gazed at the dark sky, as if it was to blame for everything that had happened. It grew darker the longer he sat there, reds fading to black and bringing with it a silence more complete than anything Tony had ever experienced.
“We should go.” She sighed. Tony said nothing and resumed watching the sky. She pulled him up and he wrenched his arm free, stumbling back.
“I can’t leave him,” Tony whispered. “I promised.”
“Please.” She muttered, her voice devoid of anything except exhaustion. Unbidden, a sob slipped past his chapped lips, tiny and quiet. He forced himself follow her. Each step pushed his body deeper into exhaustion and he teetered on the edge of passing out. He retreated deep inside his head, into a place no one could reach him. He shut down, until he was no longer aware of anything except his aching grief and crippling guilt. He stared unseeingly out the window of the ship, watched as they flew from Titan. Further and further from Peter.
In that moment, Tony hated himself.