Hey, Frisk can't help where their words trail off. They're just thinking, mulling. They're talking out loud more and more here in the castle than they ever did back home.

"Doesn't need to be. 'Specially when...all the stuff that happened was just an accident, when she was working on stuff for Asgore that could get monsters out faster."

Because that goal, at least, matters to Chara, Frisk is sure. They killed themselves for that, and Frisk knows it, and Chara knows that Frisk knows it. Even if...they killed monsters after being brought back, too. Made by that weird other.