Sei is dumb he is using the logic of his depressed policeman dad and peace loving modern upbringing in a world where two insanely powerful brings are at odds, where there are literally different races and discrimination, where there are people whose jobs are to kill, where the throne is decided by personal strength (cause Aries alone can bring a country to its knees if he tries), where an entire race is a created being with a surface level of free will just for the sake of seemingly war or fun (idk why the goddess made the demons), in this type of world he can't realise the fact that his ideal of no killing cause people are sad and lives are precious because he isn't an insanely strong being that could massacre everyone if he wished and that the lives of many only depend on his mood. Sei just has like no awareness of the situation he is in and wants to protect lives from two beings (maybe three if you count demon lord) that could crush if he does something to annoy them, like protecting the people they were fighting against and wanted to kill the other races for treating them bad, when in reality it only matters of they were strong or not. If MC was weak she would've died in the birdman shed or killed by her father for being unsightly. But because she was strong she was able escape from that life. Because the goddess is strong she can make demons that kill people for the sake of killing people. If the goddess was a bitch ass weakling she would t be able to do anything. But because both MC and goddess are strong they can do what they please. Sei thinks that they are wrong because justice says killing people is bad. He doesn't realise that if he was MC and strong as hell he could do what he wants and try to implement justice and say killing people is wrong don't do it otherwise I'll kill you.
Bleh this rant about sei's character type and winner is king is making me feel depressed because of how dumb sei is that he doesn't realise that you can't do anything when you're dead so the winner can do whatever they want while they stay alive.