Disclaimer: I do not own Persona 3.
Even if he has to tear apart every single stone barehanded until Port Island slides into the sea, if he has to fight reality with clenched fists and teeth until his body weeps blood, Akihiko will never give up the search.
Spoilers for the October full moon!
Thanks to:
SecretBox, my wonderful beta and friend.

as the day fell up

He lunges forward, sinking one red-gloved hand deep into the oily blue-black surface of the Shadow. When he pulls it out with a sick popping sound, the creature falls, fading into a dusty stain amidst the bright blood on the phosphorescent floor. There are still four more, their masks split with the cold smile of a hollowed-out skull.

You've changed, Shinji.

The Evoker is at his temple, stinging his fingers with cold as he pulls—

Caesar rises before him, terrible and great. Sparks jump from its sword, the tip flickering blue and back again as it raises the Earth high with one hand. Lightning crackles from outstretched fingertips. Three down, their faces shattered on the tile.

You haven't.

The last shudders and lashes out. Caesar deflects the blow, but the creature's cold touch sticks like a splinter under his skin.

His Persona is gone, and the Shadow is still moving. Coppery blood yields to its bite; his fingers flex in their gloves as anger takes over. Awful cold shivers through him as he buries his arm elbow-deep in the writhing, shrieking monster, but its skull-mask is broken and it has left in new mark on Tartarus' halls.

I wish you hadn't.

He gulps down a lungful of air and turns back, scrunching his cheeks in a forced smile to say it's all right. His companions are staring, transfixed; one stands dumbly with his Persona still beside him, thick plumes of smoke rising from the winged fiend. It vanishes as the boy's concentration breaks, and then he's grinning, laughing, triumphant as always, hiding his hysteria.

A red wound scars the girl's arm, and wet glimmers beneath her dark lashes as she bites back a cry. Next to her, their so-called leader has one hand on her shoulder and the other on his Evoker, raised to eye-level. He doesn't even flinch as the machine's scream rips through the silent corridors, and in a flash of white hair and red eyes in a dark face, the blood has dried and the cut has healed. She isn't crying anymore.

Just shut up and kiss me, would you?

Fuuka's voice breaks through the silence, and she tells them to come home.

He takes the lead and brings them home. They follow without question, chattering, unknowing; the Shadows would eat them alive and suck out their marrow given the chance, but ignorance is bliss, and they are all too unaware of the fate that has been given to them.

Himself included.

That's your solution for everything.

Exhaustion overwhelms him as he escorts them down the steps leading to the Shadow nest; the gate is just beyond their reach and they are due home for a last midnight snack and little sleep. He staggers, stumbles on his shoes, and falls. The flagstones knock the breath from his lungs, and his friends' screams echo in the night. Their faces, torn with worry, crowd his vision, but he swallows his pain and gazes past them.

Tartarus leaves him speechless. All the soaring towers and battlements are towering above him in a tangle of green-gold stone and iron, shimmering at an odd, somehow off angle in the light of the Dark Hour's moon. Only the girl's hand shaking his shoulder reminds him to breathe, and he stands.

He doesn't apologise, doesn't explain when they ask him what happened in voices tinged with panic. The question is what went wrong and when, but he doesn't say so, and walks them back to the dorm in silence.

Mitsuru greets the quartet with smiles and ushers them to bed. Only he stays behind, sending off the younger party with a curt nod of encouragement and the praise that they've come to expect. In the dim light of the lounge he finds the couch and falls upon it, letting his eyes flutter shut. His Evoker is still clutched in one white-knuckled hand.

I love you, Aki.

His eyes snap open, and he is vaguely aware of Mitsuru sitting down beside him and prying the Evoker from his grasp.

"I know that look," she says, but he is too drained to even look her way. She trails her jewelled nails up and down the machine's metallic surface, a look of great pain on her beautiful face. "He's gone, Akihiko. And he's not coming back."

Suddenly he's on his feet, one hand fisting in her collar, jerking her upright. He sees only the confusion and fear in her eyes before he backhands her in a flash of sculpted fingers. She stumbles back, crashing into the couch as her knees give out beneath her. Mitsuru tumbles onto the cushions, her hands to her cheek, dark eyes wide.

He doesn't regret it, not even as he storms out into the cold night.

I love you, Aki.

Akihiko runs through street after street blindly, ducking through alleyways and cutting across busy highways in his hurry to get away from Mitsuru, from the guilt eating away at him, from everything that's ever gone wrong. Salt is pooling in his eyes, and he wonders how many years it's been.

Before he knows it, he's charging down slick steps to an empty lot. Low music drifts up from the bottom of a long stairwell, and as a sharp October wind chills him to the bone, it begins to rain.

Bitter cold bites at his skin, and with the crackle of thunder pounding in his ears, he stumbles forward. He drops to his knees as his hands scour the hard ground, bloodied fingers scraping at it in complete desperation. He's here, and Akihiko will find him—he will, even if he has to tear apart every single stone barehanded until Port Island slides into the sea; if he has to fight reality with clenched fists and teeth until his body weeps blood, he will still do it.

I love you, Aki.

The only illumination the smothered sky gives him is an eye-searing flash of lightning against the boiling black clouds, and as he claws at the pavement and his body shakes with a raw, broken sob, he decides it will have to be enough.

Because he knows, he knows

I love you, Aki.

He slumps against the soaked ground, taking in deep breaths of air, laden heavy with rain. Water is streaking down his face, and if it weren't for his blotchy cheeks and the glistening in his burning eyes, even he wouldn't know if he was crying or not.

Suddenly he's screaming, rearing back and punching at the stone. His knuckles bruise red and blood trickles down his arm, but he does not feel the sting, and strikes out again. He's gone, gone, gone, just like Mitsuru said. Akihiko's been told time and again that he's not here, he's not anywhere anymore and—damn it, Shinji, why are you so selfish?—he has never hated anyone so much and so hard in his fierce life.

I love you, Aki.

And as Akihiko straightens up and turns his face toward the sky, as the rain washes the blood from his fists, he knows he has never loved so much, either.