If you don’t care about recruiting randos, then this trait is useless. Furthermore, it takes a long time to grind up to the point where you get the Hero Banner. On the other hand, the -1 affection for all princesses makes it a lot harder to (peacefully) recruit princesses, and by extension harder to recruit NPCs of that princesses’ race.
Prince Knight: +1 affection with every princess.The most useful traits in the long-term are:
#Princess and conquest free
(Tho ofc feel free to pick what you want for RP reasons – they can suit your playstyle better, nothing’s really locked out permanently and you can always NG+.) The ones that boost the Knight’s stats are a bit more useful since stat points for the Knight are scarce and become very expensive at higher levels, not to mention the Knight’s level cap of 30, but they ultimately provide only small combat benefits (and your Knight usually won’t be doing most of the fighting either). Most of the Knight traits provide benefits (affinity or items) that can be earned in-game at some point or other, and thus won’t be that useful.Generating Niu’Ya also gives you free heals if you meet her (and she’s just a cute and peaceful girl in general uwu). You may want Amelie to generate though, to recruit her for the achievement, so set the number to max.
The number of active/travelling NPCs mostly affects who wins what battles in a war, but the ultimate effect on the game is not easily predictable.