Another pulse of energy from with Zoe pushed her face towards Casey's, close enough so that they could feel each other's breaths as they exhaled. Casey could feel on her face how much more rapid Zoe's breathing was becoming as her desires was manifesting more and more obviously, and she soon realized hers was speeding up to match, especially once the small space between them closed and their lips met. It wasn't clear whether it was Zoe or Casey who had initiated the kiss -- perhaps it was both of them -- but however it started, that would be the herald for the changes to come, as the demonic energy building up within Zoe finally had an outlet to pour through. Zoe's body shifted back towards its demonic form rather quickly, the meager makeshift clothing she had stolen from the mall soon failing in their impossible task of holding back the power. Her already-too-tight shorts tore open at their seams as her thighs regained their previous fat and muscle, the pieces being pushed off by her re-emerging spaded tail. Her pseudo-crop-top held out a bit longer against Zoe's resurgent bust as the tight embrace between the two women limited its stretch, but each pulse coursing through Zoe's body added a little more pressure to the straining threads, a little more sensitivity to their touching flesh, a little more clouding seeping into Zoe's mind of the desires of the succubus within her, until the re-emerging stubs of her demonic wings pushed out from her back, cutting through the fabric and letting their ends flutter down to the sides. Her skin had begun its shift back to the crimson red shade of her succubus form.
But even through the sudden relief of that build up and the sudden wave of lust that was unleashed with that kiss, the same stubborn part of Zoe's mind that had previously held out against the initial succubus attempt to corrupt her soul did its job again, retaining enough clarity to notice that it was trying to get through to Casey. Already she could sense the same kind of power building up from Casey, the otherworldly lust that could overcome the human mind without vigilance; already she noticed Casey becoming more and more impassioned in their kiss, like a thirsty dog finding a desert oasis. Another pulse through her body pushed Zoe's breasts out to their previous EE size, enough to pull her face away from Casey and break contact.
Casey gasped for air once Zoe's lips left hers. "No, Zoe, come back, I [i]need[/i] this..."
"C-Casey, wait." The little stutter in Zoe's words underlined the effort Zoey was expending to keep things from getting out of control. Casey opened her eyes to look at Zoe, getting her first look at her friend's new face -- she let out a gasp of surprise mixed with lust as she saw Zoe's facial features up close for the first time, softer yet sharper, exuding power but also a peculiar sense of comfort even as her skin shaded more and more towards an inhuman crimson red. "You can feel it, can't you. The power, the desire..."
Casey inhaled sharply, as if on cue she felt an upwelling within her, a desire that was both stronger than anything she had felt before and yet something she somehow knew could be satisfied by the being in her arms, so tantalizingly close. "Y-yeah...Zoe, is this-"
Zoe nodded. "It is a great power. But it is also a dangerous one. It tried to turn me into something I could never want. It wants to do the same for you."
Casey let out another gasp, both from the greater understanding of the stakes and from a heat coming from her stomach -- she brought a hand down there to feel what was going on. "It's...my abs. They're...I can feel muscles there."
"Listen to me, Casey." The concern Zoe had for her friend, the desire to keep her soul safe, was enough to counter the growing lust she felt inside herself. "This'll be unlike anything you've had before. And if you let it take control of you, it'll be the last thing you'll have. Whatever happens, I want my friend here with me." Zoe's still-human blue eyes gazed into Casey's. "OK?"
Casey looked back at Zoe, took a deep breath, and nodded. "Lead the way, Zoe. I trust you."
Zoe nodded back. Time to prove this wild experiment. Zoe kept one hand around Casey as she quickly but carefuly began to remove the latter's clothes -- one set of tattered clothing was enough already. Casey gasped again as another wave surged within her just as Zoey was able to remove her shirt, bringing Casey down to her knees as the heat coming from her body got stronger and stronger. Zoe tossed the shirt away before getting down to her own knees to follow, seeing Casey's hands go to grab around her thighs and hips which were slowly but visibly expanding within her jeans; with Zoe's new physical strength as a succubus she helped pull Casey's jeans and panties off her hips before they got torn up by her changing body, helping Casey back up on her newly-lengthened legs, thicker thighs, and widened hips.
Casey managed to find her breath after the latest surge, stumbling slightly on her new legs before being caught by Zoe's arms. Casey could feel the slender yet strong arm wrapped around her back, the taut yet somehow soft skin of Zoe's abdomen against her own. She looked up at her demonic friend, eyes filled with a mix of desire and fear which gave way to a hint of calm within the storm. "Zoe..." she let out as brought a hand up towards Zoe's face when the next wave welled up within her, pushing up towards her face and chest and causing her hand to fall down upon Zoe's breast and grab hold of it.
Zoe gasped at the sudden move, her own rising tide of unsated lust coming to the fore of her mind which to this point had been focused on sharing the gift she had with her new serv- [i]No![/i] her mind cried, her [i]friend[/i]. The demon part of her railed at the arbitrary restrictions, demanding to take what was hers. But no -- her own transformation had been finished already, it was her duty to ease Casey into this new world. Casey trusted her, and Zoe was not going to betray that. Still, Zoe allowed herself a moan of pleasure at Casey's unexpectedly forward move, head tilted back so that she didn't witness Casey's facial features soften and sharpen like hers had, nor the ballooning of Casey's previously-flat chest until Casey let out a mixed cry of pain and pleasure as her now-too-small bra fruitlessly tried to contain the ballooning orbs, the areolas growing and darkening as they slipped out from the cups until the bra straps snapped apart, letting them grow to F cups. Casey used her other hand to pull the ruined bra away before she began pulling herself towards Zoe, her lips trying reach Zoe's even as her new breasts pushed back, both physically by pushing against Zoe's pair and mentally with such a new rush of sensations that Casey could barely stay lucid. She brought a hand down underneath and began rubbing her pussy to stroke it on. "Oh, God, yes!"
The rather ironic cry brought Zoe's mind back to what was happening in front of her, both physically and with regards to Casey's soul -- she could sense it starting to change, becoming like what the succubus spirit had tried to do to her back in the mall. "Casey -- ah! Almost there! Hold on just a bit more!" With a free hand, Zoe began tracing a shape upon Casey's chest above her new breasts, a circle followed by more lines within it -- the Succubus Seal. Except, of course, with some deviations from the original, like the one on herself which preserved her own soul. And a thought about what had transpired that might have allowed such a miracle to happen...Zoe purposefully stopped herself from finishing the altered Seal, turning her head up to look at Casey. "Casey!"
"Mistress Zoe!" Even in the throes of pleasure, Casey opened her eyes -- perhaps just in time, as Zoe saw the inky black of total possession had started to creep in from the sides.
Zoe had to hurry. "Guide my hand to finish the seal!" [i]And knock it off with the brainwashing![/i], she shouted mentally at whom she knew was responsible for her new address.
"But you can do it for me, Mistress, can't you?"
"I don't want a slave, Casey -- I want my [i]friend[/i]. Take my hand and let's finish this!"
Even though she didn't really understand it in that moment, Casey followed Zoe's instructions and took hold of Zoe's hand, letting instinct guide her own hand in moving Zoe's to finish the now-doubly-altered Seal. At once Casey gasped as the Seal on her chest glowed, her skin turning a dark blue around it and rapidly spreading across her body. Her hands couldn't stay away any more, running all over her body and trying in apparent vain to sate the need in her new breasts and pussy. An onrush of thoughts flooded her mind of the basest of carnal desires, overwhelming were it not for the Seal granting its power, overriding were it not for the alterations and help from her Mis- no, her friend. Her friend who, even in the throes of her own struggle against the allure of the succubus, turned down power in favor of keeping her friend free. The inky darkness that came for Casey's soul would be pushed back, letting Casey share in the miracle that Zoe had pioneered.
Zoe held onto Casey's transforming body, providing her stability for the rapid changes coming and watching her grow in height to become closer to Zoe's, watching the horns erupt from her friend's forehead, watching her new wings unfold from her back and spaded tail emerge from her ass. So focused on Casey's new form she was, Zoe hadn't realized her own needs were being addressed by her own succubus instincts until she felt her tail pierce into something warm. She remembered the feeling from before back at the mall bathroom -- her tail had entered a pussy. But not hers -- her own burned for release. Which meant...
Zoe looked back at Casey's eyes, still the brown color of her previous human form but now paired with a rather mischievous smile. Casey may have kept her soul, but she was still eager to try out her new succubus body and return the favor Zoe had just given to her. Zoe let out a moan of pleasure as she felt a different tail tease her own folds for a moment before slipping inside -- evidently, Casey was a quick study. Zoe responded by pushing her own tail farther into Casey. With the throes of ungodly passion they leaned closer together to kiss once more, their large breasts pressing together to only heighten the pleasure as they both climbed, reaching heights neither of them had ever experienced prior until they both broke the kiss with a simultaneous cry as their succubus pussies clamped down on the other's tails, their respective Seals glowing as Zoe's second and Casey's first orgasms crashed over them.