[The name is like a stab in the heart to Asriel. He physically flinches, because no, that's not right, how could it be Chara? Chara is dead. This other him - the Flowey Papyrus knows, he could be mistaken, blinded by grief he didn't understand, like Asriel had been, couldn't he?]

No, no...their name is Frisk, and they wouldn't ever kill anyone if they could help it, and they're here and safe just like we are!