The next time comes much more quickly. "You are still too impatient," he says, sitting down beside her.

"I'm really no good at being alone," she says, smiling ruefully. "I tried it, after Order 66. I knew I'd never be able to stop running, and setting down roots would only make running more difficult. But I was terrible at keeping my distance." The smile falters as she says, "It would've been more merciful to kill me than to strand me here."

Vader tries to shake off the weight of her grief. "I already told you that it wasn't mercy."

A sad chuckle. "It really wasn't." Her hand snakes over to his, and she laces their fingers together. It's with some effort that he manages not to shudder. "Actually, I'll probably die if I keep doing this." She leans her head against his shoulder, her body relaxing. "Would you prefer that to plunging a lightsaber through my heart? It'll save you a trip, if nothing else."

His throat tightens, though he's not sure if it's because of his own emotions or hers. He wants to say that it would make no difference.

It would be too obvious of a lie. "I won't leave your fate up to others," he says.

She sighs contentedly. "Yeah, I figured. It wouldn't please your master if I ended up just wasting away. I'm the ultimate test of your commitment to the Sithy way of life." She turns slightly to give him a grin. "No attachments for the good little Sith Lord."

"It isn't about him," he insists, almost cringing at the petulant cadence of his voice.

She uses her free hand to cup the side of his face, the tips of her fingers trailing over his skin with aching gentleness. "I know," she says. "But you're just too easy to tease." She traces over the curve of his cheekbone. "If you allow yourself to love, then you remember what your enemies are fighting for. And that makes it harder to kill them all in cold blood." She moves up to his eyebrow. "Plus, the pain of losing me will only make your connection to the Dark Side stronger."

Always so astute, his Ahsoka. And cruel, to spell out so plainly what he'd only ever seen in half-formed musings, buried before he could examine them too closely. He'd known, of course. From the first time he'd sensed her again, his path had been clear. And he'd not deluded himself into thinking it would be a frivolous, mechanical task.

If it were, his Master wouldn't be so keen to see the conclusion. So...forthcoming, with information on Ahsoka's whereabouts. A test so easily passed would no doubt bore him.

But he hadn't allowed himself to dwell upon the specifics, either. Like how her death would be necessary eventually, even in the unlikely event that she'd agreed to join him. Or how delaying the inevitable would make it all the more unpleasant.

He disentangles his hand in order to pull her to him, and she relaxes obligingly into the embrace. "So your objective is to cause me more pain?" he asks, stroking her backmost montral.

"Damn right," she replies, voice slightly muffled against his chest. "More pain, more power, right? You really lucked out, getting such a considerate Padawan." She pulls back just enough so he can see her twinkling eyes. "Or maybe I just wanna make sure that one day, years from now, when you look at Palpatine's stupid wrinkly face, you think, 'Gee, I sure wish that my extremely talented Padawan was here to help me finish off this nerfherder. Too bad I killed her. That was super dumb.'"

He almost laughs, but the implications are too grim to sustain his amusement for long. Killing Ahsoka means more than simply losing the chance to ever see her again - a bleak enough prospect on its own. It also means killing any chance he has of ever being free of his Master.

It was an act of total submission. Just as Sidious designed.

She must have picked up the art of cruelty from Obi-Wan, he muses, as he bends his head forward to kiss her brow. "You would make a fine Sith," he murmurs.

She shifts slightly to catch his mouth with her own. The assault of her emotions is more restrained this time, but he's no more prepared for it than before. He doesn't fight it, however, and the wash of her affection is like a cleansing fire, burning away all of his fears, all of his doubts.

He is left entirely hollow when she pulls away.

"Maybe I would," she breathes, very close to his ear, "but I like being able to love."

Through the ache of emptiness, he can feel that she's starting to fade. "Don't go," he says, pulling her even more tightly against him. "Please, just stay."

"I'll die if I stay." Her voice is very sad, and edged with pain. "My heart's already slowing down. But..." She digs her hands into his tunic. "I'm okay with that, if you are."

He releases her.

She pulls back so that she can face him properly, searching his eyes. "I won't be able to do this again," she says. "The decision is yours now. You know where to find me."

When he awakens, he knows what needs to be done.