Chara wouldn't want to attack Frisk unless it's a genocide or post pacifist run, and even so Chara shares the same Determination as Frisk, so they would have the same Higher Level Determination as Frisk, Which would end up in Chara repetitively attacking with the same multiple nine attack but Frisk would just survive anyway because **** logic I have Determination I can survive the blast of a god, as shown by when asriel attack Frisk, but Frisk would either keep sparing or attack Chara, but If frisk Attacked Chara, to spare for instance, would be impossible as Frisk could not harm Chara, because Frisk couldn't not harm Napstablook, and Napstablook and Chara are both ghosts, and if Frisk just continued sparing without attacking, depending on the route they done as a whole, they could be "good" and still have done a genocide route a few hundred routes ago, even though they did hundreds of pacifist route after, Chara would still hold a grudge and attack, and not accept Frisk mercy, but if Frisk only did Pacifist runs, Chara would ultimately accept the mercy of Frisk, so depending on the route Frisk did, the outcome, you pick universe