"So did I," Chara says, carefully. They had wondered if the other child might have had something to do with Sans being spared, but it everything had changed so quickly they'd been too disoriented to tell what exactly was going on. Either way, they realize there's something very important they need to ask the other child.

(We broke the barrier. Chara tries to ignore the sting of remembered failure at those words.)

They lower their knife, looking at the other child intently. "Alright... I believe I have an idea why our timelines may have diverged so radically."

A deep breath.

"Listen. You were sharing your body with me, correct? But. At any point in your timeline, did it ever seem like there was... someone else?"