Sans winced at the way the anomaly roughly tugged at Rose's soul, ripping it away from his own blue magic. The anomaly didn't seem to understand how fragile souls were, even human souls. Even when he was using the full force of a gravity attack, it moved her soul anyway, not caring about the subtle tears that it made.

He could confirm his guess now that she'd been intentionally not using her shields before, because now they came back with full force, pushing him away. There was no chance of reaching her soul now.

Had she been holding back for real, or had that just been to lure him in close? He'd thought he'd been reading her correctly before, back in the medbay, and that she'd meant what she said, but now he wasn't so sure.

How much could he blame the anomaly's control for the emotions he was sensing? Sans could feel the waves of malice rippling off of Rose, and it weakened his already incredibly low defenses.

While before her outer shield was soft and blue, now it was burning like fire, and one didn't have to be an expert at reading expressions to see the fury in her face.

Now freed, she took a fighting stance, well-balanced and ready to spring, one hand on the ground, as she locked her gaze on him like an eagle targeting its prey.

As she did so, the red fire in Rose's eyes died down into a hazy, calm gray that was somehow even more disturbing. The anomaly's presence was more powerful now. It was like what had been there with Frisk, guiding her movements, so subtly that it had blended in with Chara's presence at first. But now it was somehow...more. Stronger. It was impossible to miss the threads of its magic.

Rose rushed forward lightening fast and drew her melee weapon, and only Sans' quick reaction speed saved him from her strikes. As time went on, she fought more and more with that absentminded, heartless style he had come to know only too well.

"it's such a stupid, familiar dance-"

Sans thought as he dodged, his mood blackening quickly. It was hard to care. This time he didn't even have to force himself to care, right? There was no one left here to protect, everyone was dead, the king was dead, the world itself was dead, there was nothing left...

He tried shortcutting away, farther than she could run in days. But she tunneled, following him.

As she came out of the tunnel, she saw him raise his head and give her that look of anger she'd seen him cast on others so many times, or at least the other versions of himself had.

The darkness that surrounded them made the glare in his eyelights and the glow of his magic stand out all the more, and she backed away a step.

"you're not just a puppet," he said. "i know it has to be the real you doing this, because i read how that skill of yours requires your imagination."

Her eyes flickered a bit at that, but it wasn't enough.

She came at Sans again, fighting coldly, silently. As he dodged, he felt his stamina drain as the malicious intent choked his will to live, and he prepared to die again. Would he come back this time? This wasn't his own timeline. Maybe the rules were different.

Part of him almost -almost - hoped not, so that the nightmare would be over, for him at least. It wasn't like it had been an option before, knowing the world would just get reset again. He'd considered it thoroughly in order to determine if his not being around might lessen the anomaly's interest in continuing to kill. Along with more emotion-based reasons.

But, he wondered, what would it mean for one anomaly to control another, especially when one of them had her abilities? Would that make them twice as dangerous, twice as unstoppable, or more? How many timelines would they destroy besides his own? With that thought, giving up wasn't an option.

However, even the magic that connected his bones was feeling weak and unstable, and he felt on the verge of collapsing. He felt himself sink into that familiar despair that came before every killing blow.

In desperation, Sans tried one more thing.

"is this really all you are, ~~~~?" he asked, using what you thought of as your real name.

...

Hearing that, you paused, frozen in mid-strike. His hope grew a little at that, and he pushed on.

"where's the girl who let me attack her for hours, without once fighting back, because you wanted to save me?"

Finally, he saw a break in the fog of your mind, as you shuddered and stopped for a moment.

That name wasn't something that belonged to the dark parts of your past, and hearing it broke some of the anomaly's control over you.

You were still mostly trapped in a nightmare constructed of fears and traumatic memories, but it seemed you'd regained a bit of yourself back.

You started moving again and continued to fight, but Sans could see something was different now.

You no longer fought with that dispassionate, efficient focus on making the kill, where no move was wasted.

You fought with anger and feeling, making unnecessarily wide, sweeping blows as if saying something with every one of your movements.