Light was shifting around the room, shafts of it moving along the walls and into the corners of the headboard with every twist and turn of Dean's head. It was a rare privilege, being allowed to touch another angel's halo. Nevermind that Dean was an archangel, what Castiel was doing was practically unheard of. He closed his eyes and took a deep breath. A sweet scent filled his vessel's nose, sugary and heavy like the baked dessert Dean had shown him. An arc of electricity sparked off and caught the tip of his nose, his eyes snapping open at it.
If he'd had the need to breathe, he could imagine that his breath was stuck in his chest. It certainly felt that way with how he was burning on the inside. Dean was looking up at him through thick lashes, lids sitting low as he smiled softly. The shadows of his face were exaggerated in the darkness of the room, the one under his nose intersecting his smile in a way that would unnerve most humans. Behind his eyes more light was flaring, the edges of his skull showing through his skin with the pulsing of his grace.
This moment was so private, so priceless, that Castiel did his best to memorize every detail he could. The way the freckles on Dean's skin stood out in sharp contrast to the light he emitted, the bow of his lips swollen from bites and kisses, and right down to the way his hair fluttered on every one of Castiel's exhales as he straddled the archangel's waist. Not a single aspect of this time would be lost. Especially not this, as he leaned down, mouth hovering just above the burning disc of divine light, the very symbol of their power.
Very slowly, very cautiously, his lips pressed to the edge of it. His skin tingled and sizzled with static, hair all over his body standing on end while his skin pricked with goose bumps. Dean's eyes slid shut and his body convulsed before sagging. The sound he made was one no angel should make, a broken groan that hitched in his throat almost like a hammer crumbling stone.
Castiel stuck his tongue out next, tracing along the outer edge with reverent care. Glass shattered next to the bed, the bulb in the light blown apart inside the shade. He paid neither it nor the cracking porcelain of the lamp itself any mind. Dean's hands were stationary on the sheets, but his power was reaching out, more touches than Castiel could track brushing against his skin, all drawing him nearer and keeping him in his place.
More light began flooding the room, softer and tinged blue instead of gold. His control was slipping, he was quickly losing the ability to conceal the ring sitting atop his crown, anointing him in fire and grace as a holy soldier. A warrior of the greatest creation.
The pieces of Dean he'd felt reaching out across his vessel clambered over one another like a horde of rodents, all scrambling to reach the top of his head. Dean grabbed onto the sides, his hold firm as he directed Castiel with focused purpose. Fog rolled off of Castiel's halo, frozen crystals growing and always changing as he lived and served.
Gusts of winds were blown out from one halo to another, Dean's power clearing away the mist obscuring the true shape of Castiel's. Ice chipped off as it formed, flying away to melt midair. Fissures and cracks broke the ice open, true light of Castiel's being reaching out to tangle with Dean's. He was drawn nearer still, the space between them growing smaller every passing moment. Only when their halos were an inch apart did Dean's actual hands move, one to Castiel's waist and the other to cradle the side of his neck, steadying him. A dull ringing resounded in his head, catching all of his thoughts and pulling them to focus on the harp-string vibrations of Dean under him.
The first touch made his body spasm, a shout yanked from him that was only partially his human voice. The mirror in the bathroom shattered in its frame and the headboard began splintering. Of course he was deaf to this on a human level, his eardrums were blown out, blood welling up and pouring out of the canals. He could feel claws of Dean's grace ripping into his back, though the elder angel's hands hadn't moved.
It was almost like being blind, every point of contact too brilliant for even him to handle. The first sensations that differentiated themselves belonged to memories. They weren't his, though, they were Dean's. He stilled as much as he could and latched onto that thread of Dean's being, willing himself not to be consumed with the way Dean's halo was reaching up and covering his with a determined sentience.
There was light, Dean visiting the remnants of a supernova. It registered somewhere in either his mind or Dean's that the infantile nebula used to be the Morningstar.
More light, this time blurrier, obscured by time and a want to forget. There was a face, almost like the fabric of the galaxy itself twisting and smiling down at the observer. Tears came unbidden to Castiel's eyes, clouds gathering outside to unleash a torrent of flood water into the town burdened with the presence of angels. The face was moving, words pouring out like the chirping of birds not yet made and the explosions of bombs and thunder. Even the very sound of it sparked creation, gave the syllables being and purpose.
The realization dawned on him much the same way the moon faded in as the sun set, slow and purposeful. Castiel was seeing the face of God. The words became intelligible, a sentence sung out with love and adoration. You are Brotherhood and Loyalty.
Castiel was being shown Dean's moment of creation, when God was still in Heaven, anointing his sons and daughters.
It faded away and his head twitched to the left, burying his halo even deeper into Dean's as he tried to chase the remembrance of their father. Dean soothed him, pulled him closer until his heat was all Castiel knew.
More words echoed in his mind, rippling out like a step into still water. "We're one now, Cas, you know me."
A smile split his vessel's face, his true form swimming under the confines, fluttering excitedly. He relaxed and sunk further into the archangel's embrace, allowing himself to be remade with the new knowledge implanted in his mind.