
For the artist: apparently people were complaining about season one art style.
Also along with that, apparently the writer for the manhwa left as well. That's why it seems like the characters changed personalities during the second season.
I went through multiple reddits and different Korean manhwa websites and that's what I found out. Though, I wasn't able to find out why the writer left. ( ̄▽ ̄;)

Is that really it? I found out it was because they had problems with their publication company so they had to switch artists, but the previous artist is already working on something new, and they deleted all their arts with this manwha, and that no one mentions this manwha to that artists socials out of respect or something like that. But this could be the real reason too.
I did some digging and I think I found out the reasons for the changes. (づ ̄ ³ ̄)づ