Oh c'mon! It is the era where it is normal to kill and war and blood!, the girl is so stup...

That's true, and history is also a part of education so how come she's acting like a spoiled rich girl... Stupid dumb ass FMC, in that time Peace can only be attained by blood war and conflict is inevitable and after all that comes a mutual agreement for peace to ensue (⌒▽⌒)

Um guys dont forget she comes from a different world a different era. most people dont see people getting killed or be a part or wars. You cant blame her for that. She and them will always have a different opinions.

Even I from this era think it was perfectly fine to kill at that era and I totally accept it. The problem is that she's.. mentally weak, too nice and naive and that's all to it.

IKR. The FL is reactive and NOT proactive; the story just revolves around her then she merely reacts and she doesn't make any important decisions that moves the plot. Some may say that she is a boring personality and a flat character but I think that what is truly annoying about her is this.

The mc is literally watching people die and she almost die herself. I know this is fiction, but that is a really traumatic situation to be in. She already tying to get use to the fact that she in a different time line.
All because she in another era where it was normal to kill and war happened doesn't change the fact that it can be traumatic.
Also by this statement it like say we shouldn't be scare of people murdering another person because it happens all the time.

It seem like you have a problem with mc that are nice. So is it wrong to be nice and wanting to help people.
It might be easier to know that people die and kill each other when we're not in the time period, but the mc is watching people kill each other in person and she almost die, that kinda of situation is traumatic.
Being nice isn't a weakness, and please tall me why you think the mc is naive and mentally weak?

um
This is the third time I said this today
But could you please tell me what manga we are talking about here? ^^;
I read loooots of mangas

Alright then I'll write this generally since I don't know the manga you are talking of.

Also i don't hate nice Mcs, i hate MCs who are too nice for their own good and naive, and characters who can't get it in their heads that they are now in a new era where it's kill or be killed, so they should be at least expecting that stuff like that do happen, not saying they should abandon their morals here to help people, but those who help people NAIVELY and get themselves in a trap and kill themselves is just dumb.

It's normal for people to be scared and traumatised especially since they are in another world and they are witnessing murderers and all, it's NORMALL to be petrified,
traumatised and scared, but, well, after a while they have to learn how to stand up and become stronger and be smarter and adapt to the situation and be less wavered and stand up and fight until the end of their lives. I call someone mentally weak when they aren't strong enough to GET back up and fight. In case of understandablity well, understandable, doesn't erase the fact that they couldn't fight it as well, don't know if i should even considerthat wrong, it's understandable and well.. that's it.

I might understand trauma and all. And in fact yes, it's sad, but people do in fact get used to death after being surrounded with it for a long time, it's part of the human adaptive and survival nature or else we won't be able to move on. I know what I'm saying is very inconsiderate, but.. people who are born in such circumstances or have been affected by that kind of circumstances HAVE to get used to it no matter how scarring and heartbreaking it is or else they wouldn't be able to survive, it doesn't erase the pain, scars and the experience. But it's for the best if they have to survive. Not talking about abandoning their morals though, killing people should always remain bad, but being forced to remain under such circumstances one has to learn to be stronger if they want to survive. Easier said than done though.