Chapter 10 Part 3

"She's a Sitri, Master. Just like I am. We're all horny little sluts in the end, you taught me that."

She can't help but hang her head at her little sister's words, as she sees just how far Sona has fallen thanks to her 'Master'.

"True, true… but to try and steal her little sister's man? That's a new low, don't you think?"

What! That's not… that's not what Serafall is doing at all! She's going to resist, she's going to hold back… she's not going to give in! B-By the end of the night, Sona will be free. These are the thoughts that pass through the Great Satan's mind as she refuses to acknowledge the fact that she's already begun to surrender herself to Issei, at least subconsciously.

"Mm, but Master, you're already fucking Rias and her mother at the same time. It's not like my sister and I can't share your big, meaty cock. It's more than amazing enough for both of us~"

That particular revelation short-circuits Serafall's brain for a second. No, more than that, this whole discussion is making it hard for Serafall to focus on the end goal of getting her innocent little sister back. Sona is so different, so CHANGED. More and more, Serafall is starting to wonder just how she's going to fix things… while the other half of her is plotting to see her fall before Issei's amazing pecker.

It's hard to resist against the draconic young man holding her leash, when a large part of her wants nothing more than his cock, inside of her cunt, pistoning away. As she crawls along and Issei continues to verbally degrade the two of them, with Sona agreeing every step of the way, Serafall does her best to hold back her shameful arousal, her pussy lips dripping with need that she's barely able to suppress.

Finally, they arrive at the gym, their apparent final destination all along. Once inside, Issei steps out for a second, only to return with two gym uniforms. Serafall blushes as he unclips the leash from her leather collar and then tosses the short shorts and the small top at her face.

"Here, you two put these on."

She quickly gets dressed, grimacing at just how small the gym clothes are on her body. The short shorts are giving her a near constant wedgie and the top barely covers half her bust, leaving the bottom part of her tits exposed to the world as she tries and fails to pull it down further over her tits. Sona isn't doing much better in her too-small gym uniform, but unlike Serafall, she seems happy to wear the uncomfortable, tight, ill-fitted clothing, if it'll make her precious 'Master' happier.

With the gym uniform on and her dog collar still around her neck, Serafall blushes deeply as Issei steps up to her. She stands still, even as he brings fingers up along her chest and then down over her crotch. There's a spark of magic in the air and a bit of static electricity that has her frowning as she squirms in place. Lightning magic?

"What… what was that?"

Issei just grins wickedly as he moves onto Sona and repeats the action with her. Her little sister moans happily, and then strides across the gym towards the equipment locker on the far wall as Issei turns and explains what's happening.

"Your darling little sister has been teaching me a bit of magic recently. That was a minor shock spell, from what I understand. I'm not capable of much yet, but for the purposes of this lovely evening, it'll be enough I think. Now, you two are going to play a game of tennis for my amusement. While you do so, I'll be… scoring you both. Whenever either of you loses a point, you get shocked. Whenever either of you isn't being sexy enough, you get shocked. Whenever either of you just simply deserves it for being naughty little sluts, you'll get shocked. Make sense?"

The Great Satan has never been more humiliated in her life. It's almost enough to make her reexamine and reassess her situation… almost, but not quite. Despite the fact that she's been collared like a dog and clothed in garments three sizes too small for her, Serafall ultimately just blushes and nods her head, averting her gaze from the draconic young man as she takes the tennis racket that Sona offers her.

They move to either side of the indoors court that the gym features, but just as Sona's about to serve, Serafall finds out just what the 'minor' shock spell feels like when her nipples and her clit are suddenly alight with sensation, the nerves firing from Issei's activation of the spell. She climaxes on the spot shamefully enough, and falls forward onto her face as her teeth clench together and her body shakes from the experience.

Her tennis racket falls from nerveless fingers and she hears the sound of a tennis ball being struck by a racket, before the ball itself bounces off the ground right in front of her, impacting her forehead and then rolling away. Serafall barely has time to stare at it before the shock begins all over again, as she ends up 'punished' for losing the first point.

Eventually, it comes to an end and Serafall grabs her tennis racket as she slowly lifts herself to her feet. In that moment, the Great Satan is no longer doing this to free her little sister, especially not with that wicked, conniving, uncharacteristic grin stretched across Sona's face. Now, she's here to win, and maybe to see Sona take a few shocks of punishment. Damn it, see how SHE likes it.

Sona's grin just grows wider as Serafall glares at her, and then the young devil is serving up the tennis ball and Serafall is focused on it as it comes racing over the net towards her. Then, the spells activate again and she's sent to the floor as she orgasms once more, the ball striking the ground next to her and ANOTHER round of shocks running through her as a consequence.

Things proceed similarly from there, but the Leviathan never complains. Eventually, she does get a point or two, and she relishes Sona getting shocked. The other girl never goes down on the ground though, but she does orgasm a few times from the pleasurable pain running through her most sensitive bits. Ultimately, it's obvious who's side Issei is on… and ultimately, Serafall loses the game, laid out on her back, panting heavily with her pussy juices soaking through her too-tight gym shorts as she stares up at the ceiling, spread eagled.

Issei and Sona soon stand over her, looking down at her.

"I guess you lost Serafall."

"N-ngh…"

It's hard for her to get the words out, as she does her best to articulate to the pair looking down at her.

"Hm? What was that?"

"N-No… didn't… didn't lose. Not gonna… submit. Not gonna surrender."

Issei blinks and then laughs openly.

"Oh, that bit. I was talking about the tennis game you know. Sona won. Which I guess means SHE gets your reward now."

What? There'd not been any talk of a reward… what did he mean? Serafall blinks stupidly as her little sister grins and strips out of her gym clothes. A moment later, Sona is over her sprawled form, kneeling in between her legs and spreading out her knees as she leans forward and lays a very unsisterly kiss on Serafall's lips. The Great Satan's eyes go wide at that, even as Sona's tongue finds its way into Serafall's shocked mouth.

And to her horror, she finds herself getting wetter and even more aroused than before. Issei is soon kneeling behind Sona and taking advantage of her exposed cunt to fuck her. Serafall supposes she should be focused on that, should be focused on Issei plowing her little sister right on top of her, instead of plowing HER like he was supposed to.

That's not what the Leviathan is focused on though, not what the 'magical girl Levi-tan' is paying attention to. No, Serafall's undivided attention is on Sona as she and her little sister kiss, and feelings that Serafall had buried long ago end up resurfaced. Because in the end, the Leviathan and her fellow Satan, the Lucifer… they share a deep, dark secret. Not exactly hidden, but also something that both of them would never act on.

Serafall… she was as much a siscon as Sirzechs was, in the end. She loved her little sister with all her heart, as much as Sirzechs loved Rias, maybe more… or maybe not. She'd always suspected that Sirzechs harbored feelings of lust for his little sister that he would never act on. She KNEW she did for Sona. Serafall had also been moral enough to know her feelings for Sona were wrong. The power disparity between the two of them, the age gap, and least of all, their familial connection that caused such desire in the first place, had left a relationship impossible.

She'd settled for loving and lusting after her little sister from afar, keeping an eye on her, keeping her safe… but she clearly hadn't done a good job of maintaining her So-tan's innocence if this was where they ended up. And yet… and yet, wasn't this everything Serafall had ever wanted. Against her better judgement, the Leviathan's hands come up and latch onto Sona's waist, even as Issei continues to plow the petite young woman as hard as he can.

The sounds of Sona's cries are muffled by Serafall's lips, but the sounds of Issei's grunts and his cock thrusting away inside of Sona's cunt also seems muffled for some reason. In that moment, Serafall's entire world has zeroed in on a pinprick… her So-tan. She begins to kiss Sona back, deeply and thoroughly, passionately even.

Because, Serafall sees a way forward now. She sees a way to make her long time fantasy a reality. All she has to do… is give in! If she gives in, if she submits to Issei in this moment, not only will she get his big, hard cock inside of her sopping wet cunt, she'll be able to have as much fun as she likes with her little sister. They'll be equals at Issei's feet, and she'll finally get to enjoy her darling So-tan, just as she is now.

Serafall's hands suddenly move from Sona's waist to her tits. She grabs onto the younger devil's nipples and twists sharply, causing Sona's eyes to go wide as the Sitri heiress cums on the spot. Her orgasm is explosive, powerful, and most importantly, unexpected. Issei grunts as Sona's inner walls milk his release from him, and soon he's filling her womb with his seed for a second time that night.

As an exhausted Sona collapses atop her, Serafall drags her darling little sister off of her and makes eye contact with Issei as he looks down at her with a raised brow. Biting her lower lip, Serafall squirms and then spreads her legs wide, even though she's still wearing the ridiculously tight gym clothes he forced her into.

"I… I submit. I want it. G-Give it to me."

A wide, wicked grin spreads across Issei's face as he kneels between her legs, bringing his massive schlong, slick with Sona's juices and his seed, to bear on her covered cunt. Serafall flushes a bright red, the pig-tailed 'magical girl' acting more like her carefree personality than her actual age in that moment. In the end, this was nothing like facing down a bad guy from her TV Show. No, this was real life… and while Serafall might have lost her wager, she was about to win a whole lot more, simply by giving in to the newest wielder of Boosted Gear.

Issei leans over her and plants a hand beside her head, even as he holds his cock steady at the entrance of her covered cunt.

"Beg me. I want to hear how much you want this."

Serafall shudders, but in the end there's nothing she can do but what he says. Nibbling harshly at her lower lip, the Great Satan eventually speaks, and once she starts, its as if the floodgates have opened up.