Spoiler: 5x19 but AU
Note: This was done for the Gabriel Kink meme on spn_gabriel. The prompt was: girl!Sam jealous of Kali when she found the two used to be lover and Gabriel tried to convince her that Kali is his past and that Sam is his present and future. Also, Sam's always been a girl.
Sam knew she was being silly, Gabriel had been alive for several millennia before she'd met him, it was stupid to think that he hadn't had lovers before her. Hell, she knew he'd loved to conjure up lovers for himself before they'd become a couple and it had never bothered her. But Kali was different, she was beautiful, powerful and had an undercurrent of danger that would attract any man, let alone an angel. Plus Kali didn't have demon blood in her, she hadn't fucked around with a demon and started the Apocalypse.
As she, Dean and Kali and Gabriel tore away from The Elysian Fields Motel after Gabriel left a fake of himself to hold off Lucifer, Sam tried to not to wallow in jealousy as she listened to Gabriel comfort Kali. Gabriel and Kali had a bond that went further than anything she and Gabriel would ever have. She slumped in her seat, ignoring Dean's looks and wishes to be as far away from this town as possible.
They were three hundred miles away from the god motel before Kali announced that she need to get back home and explain what had happened to the other gods that hadn't attended the conference and wait for Lord Ganesha to get back, when Dean and Sam expressed astonishment, she smirked and said 'It'll take more than one of Yahweh's brats to totally destroy the Ancient Ones.' before disappearing. Dean drove for another hour before pulling into a motel parking lot. As they got out of the car, Sam realized that they'd been so occupied with getting the victims of the gods' buffet out of the motel and confronting Lucifer, they'd forgotten their belongings and weapons but a quick snap of Gabriel's fingers solved that problem.
After getting their room and the requisite showers and putting up the wards, Sam curled up in bed, wishing that this miserable day was over already. She hadn't been in bed more than a few minutes when she felt Gabriel slide into bed behind her, but when he touched her shoulder, she flinched.
"What?" She felt terrible hearing the hurt in his voice, then she felt him touching her mind and then a soft 'Oh'.
"You're jealous of Kali." Gabriel's voice was surprised but gentle, he gently gripped her shoulder and gently rolled her over so that they were face to face.
"Sam, baby, there's nothing between me and Kali anymore. Yeah, I still care about her, but I love you. I never felt the same for Kali as I feel for you." Seeing the hurt still Sam's eyes, he sighed, "Sam, do you know the real reason why I showed up? I wasn't supposed to, do you know why I did?" When she shook her head, he smiled softly, "I came because of you. Yeah, I skipped ahead to see what happens, but I came because you were in danger."
Sam suddenly felt very petty and stupid, "I'm so sorry, Gabriel, I-"
Gabriel kissed her forehead, "I know, I should've talked to you before I did anything, but I was afraid of Kali finding out that you were someone other than Lucifer's vessel." At Sam's confused look, he sighed again, "Kali can be very jealous and I was worried about what she'd do if she knew you were my lover, even though we haven't been lovers in centuries."
Sam nodded, still feeling very stupid for not trusting Gabriel in the first place. "I'm sorry, Gabriel, it's just that when I saw her and you mentioned that you'd been lovers, I-"
Gabriel chuckled, "I know. You Winchesters and your damn insecurities." He kissed her forehead again and arranged them so that she was resting her head on his chest. "Kali's my past and you, Samantha Jane Winchester, are my present and future." Sam snuggled into his arms, the Apocalypse could wait until tomorrow.
Kali couldn't believe that Loki, Gabriel, whoever her former lover actually was, had been foolish enough to think she wouldn't know the Winchester girl's connection to him. They absolutely reeked of each other, plus the girl bore the mark of a mate of a god. Seeing him with the human girl destined to be Lucifer's vessel stirred something in her that she'd thought she'd long ago forgotten; an ember of jealousy. Yes, she and Gabriel were no longer lovers, but the thought that he had found love with a human rather than with a goddess like herself hurt more than she was willing to admit.
She could destroy the girl and the revenge aspect in her roared at her to destroy the rival, and she'd be doing the world a big favor, but she found herself unable to muster the rage to do so. Gabriel had never looked so at peace in the entire time she'd known him. Besides, she could feel the spark of life growing in the Winchester girl's womb and could not bring herself to destroy an innocent life. Plus, the birth of a half divine half human would throw an extreme wild card into the whole Apocalypse scenario Yahweh's whiny brats were so set on.
Kali smiled grimly as she left Gabriel and the Winchester girl in peace, she could go back and tell the other gods what was going on. Even though Lucifer wasn't willing to stop destroying the earth in his little tantrum and Yahweh seemed unwilling to do anything about it, there was hope for the world and it was forming in Samantha Winchester's womb. The Apocalypse was already over, and she was the only one who knew it. Kali allowed herself a laugh, this whole mess just got a lot more interesting and she couldn't wait to watch.