>>63136710There's a previously existing personality there but I don't think they have much initiative or will and are probably being puppeted because they had little personality to begin with. The spamton scream and most likely eating Toriel's pie after chapter 1 are probably the extent of their current control.
I really do think that the Kris that is opening fountains is a third entity besides (You) and Kris themself but you're right he does have a little more agency than I claimed previously.