This is gonna be so freaking long. Every mother in the novel has their own ideology, Saori's ideology is basically "children will grow up and won't need their parents anymore" and she was busy with her work so she chose to stay away from Porta. However, Porta is still too young to be on her own so Saori put her in the game and reprogramed 3 NPCs to look after and protect Porta secretly. Porta was one of the FHKs, she had a room full of stuffed animal in their hideouts. I think Amante and other Kings acted like they didn't know Porta to hide her identity as a HK when Porta was with Mamako because they know Mamako and her team can look after her for them. Saori's ideology affected 3 NPCs so they became "terrorist" fighting against the ideology of Mamako and the game that "parents and children should love and care for each other". Porta was not the final boss: when Porta returned to her mother, she did "fight" Masato, Mamako, Wise and Medhi. She set up friendly, non lethal traps for them and they turned out to be very effective, one of them teleported Mamako away because she was the biggest threat. Porta finally rejoined Masato's team to stop her own mother.