Angels have the ability to see other angels wings. But the thing was, Mavriel wasn't an angel. Castiel observed her for a long time, trying to figure out how exactly she worked. It was her wings that fascinated him the most. All the time he could see them, like a hazy shadow behind her, but sometimes, sometimes he could really see them, each feather, how her muscles moved. They were intriguing.

The first time Mavriel displayed her wings to Castiel, it had been a threat, a show of power meant to intimidate him. He had threatened her, threatened to tell the Winchesters everything about her. She had been on the offence as soon as she realised who it was had taken Dean from Hell. The angel may have stood taller in his vessel, but Mavriel's wings dwarfed his. Lucifer had always wanted her to be superior if she left the Cage, and she was fully capable of that now. Her wings cast a shadow over Castiel's own, and though she was a threat, he was fascinated.

The second time the angel had seen her wings she had stood by Gabriel's side. Sam and Dean had just found out that the Trickster was actually the archangel Gabriel, and that Mavriel had a relationship with him. Cas could see Gabriel's wings too - spread wide to show his power. Mavriel's wings could be seen, but they were folded behind her. Gabriel had a wing around her, guarding her, warning Castiel that she had his protection. His wings were light, a golden brown, hers were dark, pitch black - they complimented each other perfectly to the point that Castiel was almost jealous.

The third time wasn't long after that. Lucifer had claimed Mavriel back to him and now he was ready to fight Michael. When Cas and Bobby appeared in the graveyard she was kneeling on the ground behind Lucifer, muted by his will. Her wings were wrapped around her body, hunched up over her shoulders, crossed over each other in an effort to protect herself, now that Gabriel was gone. She was trembling, her wings fluttering nervously.

It was some time until Cas saw Mavriel's wings again, and that had saddened him. Cas had killed Balthazar in panic, he hadn't wanted to but he had. And when Mavriel had found him again she was furious. She had attacked him, and rightly so. Punches flew at him, coupled with kicks, and past her he could see her wing, spread wide in anger, fury, uncontainable rage as they cast a shadow over him. They put strength into every action, every strike and blow. He didn't fight back, he had no right to after what he had done.

The fourth time was different. They hadn't really been on speaking terms for a while, but Cas had saved her from a demon. She'd been knocked out and when she woke in the motel she asked for him. He'd been surprised but went to her anyway, they'd spoke for some time until Sam and Dean were both out the way. Then she had stood up and kissed him to his surprise, her lips were soft and warm and lovely. Behind her, her wings fluttered slightly, they weren't fully folded, peaking out from behind her, captivating his interest in them yet again. His own wings had fluttered nervously in return and she had smiled. Mav thought that it was cute. It was the first time Cas had seen her acknowledge his wings.

The fifth time Cas didn't really know why he had seen them, there had been no special cause or heightened emotion, but he had seen them again. Sam, Dean, Mav and Cas had been sitting in the Bunker, watching a film and eating pie. Cas was there because Dean had told him it was traditional for friends to get together watch tv and eat, he hadn't fully believed him, but he had joined them anyway. Mav had been sitting forward in her chair opposite him. Dean had said something to make her laugh and Cas had seen her wings, they unfurled from behind her as laughter had erupted from her lips, moved in time with her laughing. They were big and shimmering black, powerful but they looked so soft. He had stared and she had seen him. She smiled at him, knowing what he could see and she winked. But then had gone away again.

The next time Castiel saw Mavriel's wings, it was a mystery to him. He was human now, his grace stolen by Metatron. Dean had forced him out of the bunker but Mav had gone with him, unable to see him cast out alone in his condition. Some night's she gambled well enough to get them a motel room for the evening. It was one of those nights; the place wasn't bad, clean, warm, comfortable. Only one bed though, but by this point they didn't mind.

Mav had bought something alcoholic and they'd shared it - Cas was out his face and Mav was giggling like a hyper pre-teen. And then they'd kissed, and kissed again, they kissed until they collapsed on that single bed - it was then he'd started to see them, faint, on the edge of his vision. Sitting against the headboard she's straddled him, kissing, pulling off his tie, unbuttoning his shirt. He'd tugged off her top, unclasped her bra and then he could see her wings, half folded, beautiful - her body was soft and beautiful and her wings were perfect. He didn't want to close his eyes for a second, lest he missed seeing them for longer. He struggled to keep his concentration, but he watched how those wings reacted to every kiss, every touch. He watched them flutter and tremble as she moaned his name. He had never considered this possible, especially after he lost his grace, but now, it was right in front of him.

He flipped her onto her back, taking in every inch of her body as he moved inside her. She moaned his name, pulling herself up to hold on round his shoulders, wrapping her legs around him. "Cas" she had begged, "please, please." He had wrapped an arm around her back, and with his other hand, ran his fingers through her silky feathers. She whined and moaned, biting down on his shoulder, shivers ran through her body. Cas continued to touch her wings and send her closer and closer to the edge. Her whole body tensed around him as she came, her wings trembled and her nails dug into her back. Cas stared at her awestruck for a second before he captured her lips passionately, cumming seconds after.

They had laid side by side afterwards, Cas still staring at Mav's wings. They were so much more tangible than angels wings were, much more real and beautiful and they were right there. "Cas, you're staring" she had said.

"I'm sorry, it's your wings"

She had laughed, "You can see them them?"

"Yes, on occasion"

"I thought so. Gabriel could see them on occasion, or if I wanted him to. Balthazar could see them all the time, who knows why."

"He was very fortunate"

"Why?"

"Because they are so beautiful, they're amazing, I've never seen wings like your's before" She had smiled sadly, cuddling in to him, remembering a time when she had had six wings, as oppose to two. She could still remember that pain, that agony. She couldn't ever forget that. Cas gently ran his hand over her wing, making her hum contently. Her feathers were so soft, warm under his hand. She stretched her wing slightly, wrapping it round Cas, covering him. "Why can I see them?" He asked.

"My wings? I don't know"

"I'm human now, it doesn't make sense"

"But you are still technically an angel." Mav said softly, she sighed sleepily, "Go to sleep now Cas"

He smiled gently, "Good night Mav"

"Good night Cas