Game we will never give as this answer. So my question is: what is he or she for your?

When you play the game, from where it appears?

For me M.S. is a person from the future, M.S. came to help, but just enough keep me alive, not to make major changes in the past.

He's a mysterious stranger.

That is true. Across different iterations of the series, his model is different, but he always finishes what he starts...

I think it'd have been awesome for Nick Valentine to say, "Yeah, I traveled a lot before settling here last year. The Capital Wasteland, the Mojave....helped a couple of people out who caught my interest. Got pretty banged up, though."