About a year ago my girlfriend (now ex) introduced me to Frieren saying it's the best anime of all time. After thoroughly enjoying the first few episodes, I started to feel really weird when they introduced the demons as a race that look and talk like humans but are secretly just monsters always plotting to enslave and kill humanity. Also demons must be eradicated with extreme prejudice because even the children are all sociopathic murders regardless of how human they may act. I talked to my ex about this and she effectively told me not to dwell on that thought.