2nd focus is on Rhonya's past (where she literally saves the world/plant life by being the Spirit Forest's protector while Gratia is busy since she's also contracted with Orphedoto. She managed to single handledly hold off controlled beasts by the demon *whose powers are basically ensnaring/enhancing negative emotions* while healing an injured Laclain. She manages to seal the demon but since sealing magic isn't her forte, it was incomplete where the demon manages to escape and becomes obsessed with Rhonya since she's a literal pure soul which he just wants to basically corrupt. The demon also went so far as to infiltrate the academy back because of the barrier, he was heavily weakened but was able to escape. But because of Rhonya's expulsion, naturally he takes advantage of this until he gets sealed for good at the cost of Rhonya temporarily cursed.
Djinn King and Elven Queen are basically characters introduced in Vol.03. Queen is sibling of another one of Rhonya's suitors, elven prince/hero Orphias. One of the few males even Schneider was wary during their 7 year relationship (depending on the translation, or there might already be inconsistencies but Rhonya is either 16 or 18. Shize is 24, Sena 23. Ryuse and Chise if memory serves me right, 19 or 21 probably the latter). Queen is aware of both Rhonya's feats where she basically taunts Schneider over how much of a moron he is and she'll support her brother all the way and they'll treat Rhonya with respect in the elven kingdom (btw her saving the world was kept shut out of her request so that her family won't necessarily add unreasonable work where they'll belittle her in the end later). Djinn King is basically someone who can sense/smell emotions better but is unaware that Schneider outright annulled his engagement publicly/the worst way possible for nobles (so basically the 2 monarchs are good and bad cop towards Schneider)
As for Misano, Schneider breaks up with her (bit its revealed she genuinely just loved him *not an isekai, just someone desperate enough to want another man* and depending on the interpretation on Schneider's words might still love Misano too *basically, he tells Misano he doesn't want to see her and blame it all on him and he can't afford to see her or he'll blame her*. Eh, either way initially, nobody gave a d*mn to Schneider's new engagement with Misano since he ignored and treated Rhonya the worst way possible, not even his uncle despite already scolding him
Demon is the major antagonist of Vol.02. Basically, in Vol.02, it focuses on a few things
*Schneider POV/centric chapters after Rhonya's departure (near the end, not only did Lexi physically face slap him at the start of Vol.02 *in the recent manga updates, it was mentioned she was away to study abroad*, again near the end, the 3 Rhonya orbiters/the one who gave their testimonies against Rhonya were revealed to have been threatened by Misano using hallucinogenic drugs and they came begging Lexi for help since they're incredibly guilty that their actions of initially bullying Misano despite Rhonya's request/warnings not to led to this situation of Rhonya's expulsion. Naturally, Schneider is already ridden with guilt since the majority of the notable named side characters are on Rhonya's side (Hansel, Lexi, the king/his uncle, Rhonya's granpa, foreign prince of the Djinn Kingdom *this was a glimpse on just how much diplomatic power Rhonya had) and again, the only reason the expulsion happened is because of Rhonya's nature of being an introvert (since the plot was literally happening in front of her eyes. And in the recent manga updates, she did ask Sena's advice on the what if he was reincarnated) and the fact her family isn't well liked by the younger nobility given their ambitious nature