Todd Howard, Fallout 4’s game director, did mention in an earlier interview, “I can’t tell you that you can play the whole game without violence – that’s not necessarily a goal of ours.” It looks like this has been achieved already, although some might actually think that it is impossible.
Dedicated players have been working at Fallout 4 since its release to complete the game sans a single kill, and it looks like Kyle Hinckley is the first one to achieve such acclaim. He managed to complete Fallout 4 with zero kills on Survival, which is the hardest mode where you can play the game in. The entire effort has been documented on video as proof, which you can view in the video above. I’m sure that this particular effort does not require any kind of lightsaber mod!