So what is the story of Asriel and Chara at the end? I think it's really quite a simple one. I think it's the story of a young human who wasn't happy living with humans, then wasn't happy living with monsters, and hopes that maybe they could take their best friend and run away from both, like Huck and Jim going on the lam in "Huckleberry Finn". And I think Chara told Asriel whatever lie they could to make that happen, playing on Asriel's desire to save his people. But I don't think Chara ever wanted to kill anybody at all, not even the needed six, until Asriel persuaded them to return to their village. #Undertale