The basic gist of the scenario:
After Sei uses the Saintess magic again and purifies the forest of both miasma and demons/monsters. Her life there makes a significant change. Even without confirmation, people view her as the Saintess for her accomplishments. People she don’t know treat her with reverence and someone of very high status.
This doesn’t sit well with idiot prince since he’s STILL under the belief that Aira is the Saintess.
At some point when Sei goes to the castle and is also being accompanied by the Head Magician. The two encounter said idiot prince with Aira as he’s arguing with Liz. The two are publicly arguing which is already bad since castle life of everyone there are thirsty for any gossip.
Liz is concerned that leaving things as they are, Aira’s situation at the academy will worsen. First among the many stupid things this idiot prince says is that he thinks that Liz is leading all the girls ostracizing Aira because of her own jealousy. Liz exasperated from that ask if he thought that, why didn’t he accept her proposal of having Aira being around other girls instead her being around boys with fiancées.
Sure, idiot prince says he has “responsibility” as the overseer of the Saintess Summoning and he says that he must protect her. Liz a bit angered, asks why he didn’t protect the other person summoned.
Idiot prince only knows “other woman” through rumors. This is where his stupidity reaches maximum levels.
He says confused as if his logic is correct that the the other woman, Sei, isn’t the Saintess. He goes on to say that Aira still needs to get used to subjugations but people want the Saintess to be involved so they faked the announcement that the achievements of the recent subjugation of the knights to be the Saintess’s.
Liz snaps and asks if he understands what he is saying.
Sei gets noticed and she only addresses Liz, trying to suggest to move this argument to a more private setting. She introduces herself as Sei to the idiot prince.
Idiot prince says “so you’re the FAKE Saintess” Sei doesn’t respond and idiot prince ignores his own kingdom’s common sense of not touching a unmarried woman when Captain Hawk saves the day. Also the King shows up here.
The King says that idiot prince is extremely rude to the Saintess. Idiot prince fights back saying it is other people. The King shoots back with “I heard you were calling the Saintess a fake.”
Idiot princes goes defensive and says that he the king is using Sei to serve as a fake since he still stupidly believes the Aira is the Saintess as she was the only one summoned. The king corrects that by saying Sei was also summoned.
Idiot prince goes “What?”
And shortly after being told by King, that both the Head Magician and Captain Hawk confirm it. He then lays more down, saying that while Sei has been doing one accomplishment after another, what had Aira done under idiot prince’s care. He then says that idiot prince has no basis for his statements without proof. It is after this that idiot prince along with his followers are placed under house arrest. Aira’s new caretaker is the other prince. Aira’s school life becomes better thanks to Liz and Aira gets some advice from Sei.
After this idiot prince is never seen again~ well he’s around but no longer has a part to play in the story