I’m not 100% sure, but they definitely made a point of usually having a peaceful option where you can rely on intelligence or charisma or other skills. 

Undisciplined

In all Fallouts can you complete the game peacefully?

riberet19

gaming

Games that you can complete without killing anyone

I'm not entirely sure, but I think you might be able to beat the Fallout Games without killing. They're definitely violent games and it would be quite difficult, but there is usually a peaceful option for completing main quests.

I do generally try to play these games fairly peacefully, although I don't hesitate to defend myself.