Rias and Akeno watched nervously as the transformation worked on Ryuko's body. Normally, such a transformation passed swiftly, and there was little physical change...even for those like Gaspar or Koneko, who were half-human, or only human in form respectively. However, Ryuko was very different. Even Gaspar and Koneko's souls had been fully humanesque, native to Earth's magical fields and the demiplanes connected to them. However, the thread-like half of Ryuko's being wasn't, and in fact seemed maladaptive to said fields, as though by nature it was meant to destroy or be destroyed by them. The way that side had lashed out and leached the life right out of things nearby, leaving only dead matter...they'd never seen anything like it. It had...killed the magic in the plants and insects struck. How such a being would react to being transmuted to a Devil was anyone's guess, especially with light magic embedded throughout her body-
Ryuko's body suddenly convulsed, her eyes popping wide open as her jaw wrenched wider than a human jaw should allow, her teeth turning razor sharp as her limbs bent backwards. Claws of the thread energy erupted from her fingers and toes, digging into the ground around her and shredding the concrete like tissue. The stone broke down and dissolved at the contact...and then erupted in thread-lined stone limbs to seize the Light Spears embedded in Ryuko's body in an attempt to pull them out. A single black bat wing erupted from her back as threads lashed from her other shoulder.
"The human side of her soul has shifted!" Akeno spoke up worriedly, having been observing the process to try and be ready if something went wrong. As they watched, the flesh around the Light Spears began to boil and blister. "Rias-sama!"
But Rias was already acting. Gathering her magic around her, she unleashed the crimson-tinged black of her unique power, magical energy so concentrated it became the essence of destruction, the special power she had inherited which gave her the title Crimson Princess of Ruin. The energy lashed out and struck the Light Spears, eradicating them in their entirety. She started to pull the energy back...but threads lashed out from Ryuko's body and wrapped around the released Destruction Energy, interweaving within it and pulling it apart. Rias tried to pull back, but was only able to retrieve the energy the threads hadn't already claimed. That energy was soon absorbed into the threads, sealing the holes in Ryuko's body as the threads folded back into her and her spasms subsided. Threads erupted from her other shoulder, taking the shape of a second wing before solidifying to match the one that had already been shaped. Her spasms ceased, and she lay still, her breathing in a sleeping pattern.
"Rias-sama..." Akeno asked nervously. "Did she just...absorb your Essence of Destruction?"
"S-she did," Rias stammered in awe. "I can't even begin to imagine how..." Her eyes lit up as she remembered what Ryuko had said about the way her body worked. "Her body absorbs any new energy to repair itself when badly damaged. It couldn't absorb the Light Spears because they were incompatible as magic first, and then as holy once she became demonic. That side of her being has already adapted to her now being demonic...which made my power compatible."
Akeno stared in awe and more than a touch of fear at the recumbent Ryuko. "That's...somewhat terrifying, if something that was antithetical to magic could adapt to it that quickly..." She then blinked in surprise. "I can't sense the Gear anymore!"
"What?" Rias demanded in shock.
"The energies of the Gear...I can't pick them up anymore." Akeno raised her hands to enhance her scanning magic, sweeping it over Ryuko's body. "It doesn't read like it was absorbed or subsumed...the only explanation I can think of is that other side of her being somehow used the Gear as a...a bridge to adapt to her becoming a Devil. As such, her overall energy signature is now so attuned to the Gear that, unless active, it can't be distinguished from her own signature."
"...stuff it with the technobabble..." Ryuko grumbled as she stirred. Her eyes slowly opened, and she sat up and stretched. "Who knew an absence of pain could feel so good?" she muttered as she rolled her shoulders, flexing her wings a few times as though she'd had them all her life before drawing them back into her body. She then squinted a bit before giving her eyes an odd roll. "Oh, good, I can turn the night vision off. That's a relief." Her eyes rolled back in the same odd way as she lay back on the ground, flexed her legs, and launched herself to her feet. "Well, everything seems to be in working order..." She then noticed Rias and Akeno staring at her with their jaws hanging. "What?"
"How are you adapting to this so well?" Akeno finally demanded in shock. "Your entire energy nature has changed, you have new limbs, and...and..." She waved her hands in frustration.
"You say that like it's the first time something like this has happened to me," Ryuko countered calmly as she stretched easily. When Akeno took a closer look, she saw the rents in Ryuko's outfit sealing themselves up naturally. Ryuko then glanced at her right wrist for a time, then shrugged. "Well, come on Rias-dono,"she stated, grabbing hold of Rias by the wrist. "Satsuki and the others are waiting, and I'm looking forward to how you spin this."
"I'm beginning to think I need to learn more from them than they do from me..." Rias observed worriedly, noticing but not commenting on Ryuko's choice of address for her. She supposed in this case, respect would have to be earned. Noticing Akeno looking rather perturbed, she spoke up. "Akeno! Inform the others of what has happened and the...changes to our usual handling of these situations. I'll be there to introduce our new member in the clubhouse after school tomorrow."
"Yes, Bucchou," Akeno responded immediately, opening a warp circle and vanishing to follow instructions.
"Am I going to learn to do that?" Ryuko asked curiously.
"At some point, yes," Rias confirmed. "Preferably sooner than later."
"Got it," Ryuko replied before leaping for the top of the nearest building, dragging Rias along behind her.
"Why aren't we taking the streets?!" Rias screamed out as they rocketed through the air as Ryuko leapt from rooftop to rooftop without stopping.
"You have wings!" Ryuko snapped out. "Why aren't you used to using them?"
"I fly with magic!"
"That's lazy!"
...this was going to be a headache.