Psychology

There are Iaros who grew up being a jerk with evil pope and there are his parents who lose their life because their loves;
Helio who grew up losing his loving parents and his uncle who attempts to takeaway his fortunes and murder him if Medeia, Sana, and his butler doesn't with him;
Medeia who raised by her parents and her brother;
Psyche and her family background of the religious traditions and experiments;
Pel and his temper when he is working as Cardinal of temple

It's Kim Jaeo's psychologies that I will never forget about.

The bully part and the syndrome of them being happy seeing other people miserable

Standford prison experiment: People with authorities will torture people below them

I like the part when their manager and her older sister reminds him that "No man is island" and he shouldn't put his social energy to her alone.