If this looks familiar, it has been previously posted to my AO3 account.
Ardyn's voice echoed in his panicked head. "Friends… Prompto… Deamons..." Just scattered words that caught his attention. He'd managed to tune out most of the Chancellor's ramblings, intent of fighting his way through the labyrinth of cramped corridors in search of his boyfriend. The thought of Prompto lost and probably unarmed in this hell-scape drove him onward.
The glowing energy of yet another deamon's life-force swirled through the air and into the Ring as yet another goblin dissipated. Out of the corner of his eye, Noctis caught a flash of red plaid fabric and blond hair.
"Prompto, wait!" he shouted and ran after him through the twisting hall filled with crates and broken MT parts. He must be terrified, Noctis though. Terrified of the deamons, of Ardyn, of the tight spaces he had to navigate. Terrified, perhaps, of Noctis himself. What if Prompto didn't know the truth? What if he still believed Noctis was angry at him, hated him even? He had to catch him. He had to tell him it was all a trick, that he still loved him and would never abandon him again. That he was sorry for everything.
Noctis rounded yet another corner at such a high speed he nearly crashed into a stack of crates. He nearly froze when he saw Prompto. His lover stood motionless and silent, not even his chest moved to indicate he was even breathing, even though he should be out of breath from running.
"Prompto?" Noctis spoke softly and carefully, approaching Prompto from the right side. He wasn't even blinking, Noctis noticed as he got closer. "Prompto, it's me, can you hear me," he whispered. Tears streamed down his dirty face when he was met with more silence. "Prompto, please!" Prompto stood still as a statue, not breathing, not blinking.
When Noctis looked closely at his face, he jumped back in shock. Prompto's normally bright and expressive eyes stared into an invisible void, lifeless and dull. Thin red rings glowed around his dilated pupils.
Noctis shook his head slowly. "No. No, no nononono PROMPTO!" Noctis wrapped his arms around Prompto, who at this point was decidedly not Prompto, but Noctis didn't care. He clung to him and wept into his shoulder. "Prompto, I'm sorry. I'm sorry! I love you, please Prompto..."
"Aw, how touching," Came Ardyn's sinister voice. "So close yet so far away."
"SHUT UP!" Noctis screamed. "Shut up, YOU did this!"
"Did I? If I remember correctly it was you who abandoned your precious lover on the side of the tracks. You'd better find him… before my deamons do."
Noctis looked one last time at the image that looked so much like Prompto but wasn't. "I'll find you. I'll save you. I promise!"