If someone criticizes me for having given a 9, it is because I read the manga and thought it was very good, the anime is not there yet
Rudeus is not the best character, but he gets better with time (based on the manga)
Eris is the best girl
Paul is a bastard who should take it in the ass
If I were the creator, I would leave Eris as the sole interest of Rudeus, but if the creator decided he would have a harem, there is nothing to be done.
SPOILER AHEAD: I thought it was really stupid of Rudeus to forgive Paul so easily. The misunderstanding between Eris having "left" Rudeus because she wanted to protect him, and him thinking she had abandoned him, was really interesting. I thought the Demon King was random from entering the academy and I hope that the manga chapters take less time to arrive more.