Or could it be that Kon is the monster, sort of. Don't the protagonist getting rejected by peoples because of a monster linked to them remind you of someone ? Yeah, it's almost like Naruto with Kyuubey being scelled in him. Maybe it's the same with Kon, the monster has been scelled in her. That explain why they got saved in the first chapter, why peoples don't seem to like Kon. Her little bro also said she see a Kaijuu back then. Also that could explain why bully girl got yeeted.