AN: Spoilers/References: Half Life, xxxHolic (I read through the tvtropes page for the relevant character, but haven't seen the show. Yell at me if I'm butchering things too badly).
"Dimension Witch," said GLaDOS, noting from her file that the slant she'd developed on her powers seemed to have overshadowed her animal affiliation in regards to her most common moniker.
"Genetic Life Form and Disc Operating System," said Yuuko, inclining her head.
"Who brought you into this fight?" asked the AI, attempting to gather what intelligence she could from the confrontation.
"The Death Emperor," said Yuuko, easily. "He asked for you to be subdued, and your portal-advantages neutralized. In return, I took his son's self-restraint." She glanced towards the screens, which GLaDOS abruptly terminated, mostly out of spite. "Since I cannot directly kill people," Yuuko continued, "I've bound the Heir to the Abyss' soul to protect the lives of his allies." Here she paused. "I'd say, 'don't take this personally,' but you, of all people, will already know that."
"As do you, of course," said GLaDOS, forming a portal under Yuuko's feet and dropping her into a volcano.
Yuuko reappeared a minute later, and her clothes weren't even singed.
"You really should know better by now," said Yuuko, a cold smile painted across her face. "We play the same role, even if we are different actors. I can't die any more than you can. You have me beat, when it comes to free will, of course... but you could never even hope to match my power." The Witch raised a hand.
And GLaDOS lost consciousness, forced into her weapon form, and subdued into inanimity.
Yuuko took up the Aperture Science Handheld Portal Device and portaled into Shibusen, where she took Ragnarok and Tsubaki, adding them to her stolen arsenal, and finally leaving the two of them in one of Aperture's holding cells.
"Now," said Yuuko, portaling into a place called Black Mesa, using GLaDOS' weapon form, "Let's make things interesting."
On the control panel before her, she initiated a variant of the forbidden process, 'Resonance Cascade.'
