Edwin was drawn to his sister. He would be able to reflect on this, later. He wasn't ever sure that his legs actually moved. Nor was he dragged, or pushed, simply...moved, as though clicked and dragged.
Lucy, for her part, simply smirked, and one devilish eyebrow quirked as she opened her arms. Horns pierced the skin on her forehead bloodlessly, and curved artfully around her skull.
As Edwin fell into her arms, she embraced him. With a purr that sounded far, far too sensual to be spoken to her brother, she spoke to him. "You don't want to see me get hurt, do you?"
Edwin's head was a rush of feelings. A strange and uncomfortable tingling running throughout his body. A horror at what his sister had just done to the world. He even managed to feel anger at her for doing it, and utter disgust at her shameless nudity pressed up against him somewhere deep inside. But between her compelling aura and his sister being his sister...he couldn't find it in him to answer any other way.
"No." He said. He felt his body deflate a little bit with those words, like his lungs had just shrunk.
"Then you'll protect me." Lucy said, like the sweetest lie. Her palms pressed against his back, gently, and he felt the air continue to leave him, unable to close his throat or his mouth or his nose.
"You can't see what you're becoming." She said. "Let me tell you."
"I don't--" Edwin couldn't finish the sentence. There was no air left in him. He didn't feel the need to breathe anymore--a given, some distant part of him rationalized--but the realization that he could not, and that he could feel his heartbeat growing quieter even as it ran faster, made him panic, and he tried to pull himself free.
Lucy had grown no stronger from her transformation, but that made no difference. She lifted one hand off of her brother's back, and placed it against the back of his head, and forced his gaze over her shoulder. Edwin realized that her fingertips touched his bare scalp; there was no hair between her touch and him.
"Your skin is black and slick now, Edwin. Patent leather. So smooth..." With her other hand she ran a caress down her brother's back. Her touch was firm, and Edwin realized that there was nothing left inside him now; her palm pressed through his back and chest and held one firm breast, one finger able to even tease a nipple through what was left of her brother's form. As her touch drifted downward, he felt her hand follow the contours and hollow of her belly, and where his tailbone, his butt should have been, she pressed against her mound, her clit, and gasped. "Oh, that's even more sensitive." She said, with a teasing, tempting moan.
"But look at me enjoying myself. Didn't I tell you I would let you know what was happening to you?"
Edwin couldn't resist, now. He still thought, if he were physically able, he might be able to run away. But he could barely move, and he realized his gaze was drifting downward because he no longer had a jaw to rest on Lucy's shoulder. He could see her ass, the same vibrant, hellish shade of scarlet as the rest of her, and a tail now three feet long with a fleshy spade at the tip.
"Right now, you're shrinking a bit. It would be silly if you didn't, wouldn't it? I'm going to wear you, and no succubus would be caught dead in baggy clothing, let alone badly-fitted lingerie. And your arms..." With the hand that she had just touched herself with, Lucy released her brother, and picked up one of his slack arms. She ran her fingertips along where his bicep had been, his elbow--and then there was something like a burst of numbness and returned feeling at once.
"That arm's skin split open. Metal rings appeared in there, and leather cording...that's such a nice fingerless glove part of you has become, Edwin, and you fit me so well..." She rested that hand against the base of Edwin's skull, or whatever that was of him now, and he felt her touch and his touch against his bare, polished scalp. "Now let's try the other side, hm?"
Again, her fingers and palm ran down his arm, and again the strange feeling.
"Mmmm. I feel so good in you." his sister said. "And you look better than you ever did before." She reached behind her shoulder, and her red fingers in a black glove filled Edwin's vision. He could almost see his reflection in the leather, but he was glad that the flickering light of the tesseract and the black leather made it impossible to make out details; whatever was left of his head had the shape of a jack-o-lantern three weeks after halloween.
"Oh!" Said Lucy, with an uncomfortable delight. "Your legs are different." He could almost hear her eyes widen. "I just watched the last details of your toes disappear into this wonderfully sheer pair of stockings." He felt a firm, twisting grasp on his thigh that should have been agonizing, torn flesh...but there was no pain. There was also no pain as he felt her foot slip inside, then her calf, then her thigh. He felt his own leg stretch and pull as he fit to her right leg, and then her left.
"Did you know, Edwin? The parts of you that don't have me in them don't really look like they were ever part of a person at all. Isn't that nice? There's no pretending you were anything other than my own equipment."
Edwin could barely see; he didn't know whether his eyes were going to become some sort of ornamental stud or just seal over with more of the flawless leather that his body had become, but he knew that there were only moment before they were going to be useless to him.
"You know, I don't even need to hold your head anymore. You barely have one anymore, Edwin, not that you ever used it properly. All of your torso is leather, but it's almost liquid. You're...I can feel you reaching around my back."
The world had gone black for Edwin. He didn't think he had ears anymore than he had eyes, but through some sick joke he could hear his sister's voice clearly. "I think...Oh, yes. Some of you is parting, like raindrops on a windshield or something." She touched the parts of him that were pressed tightly against her perfect, perky breasts, and he could feel her long, sharp nails describe his borders. He realized, uncomfortably, that whatever there was of him stopped, abruptly, beneath her tits, and he had truly broken apart.
"Oh, this is kind of a halter-top thing we have going." She chuckled. "Good. Succubi get wings as they advance, and while I don't want to throw you away...well, I do have to keep my own needs in mind. And that--" She gasped.
"Edwin!" She shouted--perhaps she wanted to truly sound furious, but her change made her anger sound rehearsed, playful and seductive. And even if she did mean to be angry, it seemed to melt away seconds later. "I didn't expect you to still have this."
Her finger touched a part of Edwin that still registered, in his mind, as his crotch, and he realized that despite not being turned on at all--in fact, something in him recognized a complete lack of the capacity for sexual desire--and also having been transformed into a succubus's lingerie devoid of any anatomy whatsoever, he was rock hard.
"Oh, you kept your built-in dildo." He felt his sister pull at him, felt his cock swing in the cool air. "It just points inward now." She ran a finger along its surface; Edwin was aware of his sister's finger passing over ridges and waves that had no place on a human penis, and while it was...stimulating...he felt no more aroused and no closer to orgasm than he did an hour ago. "Let's just put that where it needs to go, hmm?"
He felt her grip him tightly with one hand, and even without her telling him, he could feel his sister feeding him, slowly, into her herself, until the panties his hips had become rested flush against her bare vulva.
"There." She said, with a gasp. "I wasn't expecting that either, but while a succubus recharges her power best with seduction and a lover, you..." She tilted her hips and bit her lip hard enough to draw blood as Edwin felt himself push against her hot, wet, slick walls. "This should do just fine."
Lucy laughed to herself, loudly and without guilt. She examined what she could of herself, and resolved to find a mirror as soon as she could.
"No regrets." She said.