Their bond was still open, their secrets laid out for the other one to know without even so much as putting forth an effort, but Jaina refused to use it. She could feel the darkness calling to her brother - she'd be lying if she didn't admit it called to her as well - but that didn't mean she was going to intrude. Forcing Jacen to choose a side meant she was going to lose. Instead she was going to take it slow, give him the chance to work it out for himself, and hope that she could help him sort through his issues without causing him to turn to the only means that, apparently back home, he'd felt he had.
So ignoring the darkness and making certain to simply let their bond exist without using it for more than the comfort it was providing in place like this, she answered, "Because he showed up here after he died. He looks like he did in his youth, but he has the memories of everything that happened."
Her brow furrowed as she brought her knees up close to her chest, looping her arms around them. "I think he showed up as Anakin, then turned back into Vader," she confided in her twin, speaking slowly as she puzzled it out in her mind. "I don't know why, and I'm not sure I really want to know. All that matters to me is finding some way to stop him before he does decide to act."
With a soft sigh, she admitted quietly, "I'm just not sure how to do it."