Darth Vader has left us

[Saintheart]

James Earl Jones famously did the voice, but there was also a stunt-Vader, Bob Anderson (Anderson was a swordmaster - IIRC he was an Olympic fencer (bonus fact - so is Bruce Dickinson, lead singer of Iron Maiden!) and did a lot of swordfighting choreography in films) played Darth Vader in the swordfight scenes in ESB and RotJ, though I don't believe he was involved in Star Wars. Could be mistaken on that.

Anderson was the fight arranger on ANH, but was uncredited, at least according to IMDB. In fact a number of Bob's films were uncredited; I would guess the reason for it was the same reason that people do temping or 'work experience' - to get their name out there, or because the production can't afford to pay full union rates, i.e. why actors sometimes go uncredited when it's small roles. George Lucas didn't exactly have a big budget for ANH, so Bob might've agreed to cut him a break or do him a favour or something. James Earl Jones himself went uncredited on ANH on its original release, he didn't start getting mentioned on the screen until ROTJ.

And no, it definitely wasn't Anderson behind the mask for Vader during the fight scene of ANH; indeed (and not wanting speak ill of the dead) watch how Prowse and Alec Guinness shuffle their way through that duel, and it's glaringly apparent there's a different man behind the mask on ESB and ROTJ. Indeed the story is that because Prowse was (a) useless at fencing and (b) busting lightsaber props at a rapid rate, that's why Bob was put in the suit for the fight scenes for subsequent movies.

But yeah, Bob Anderson: as said, British Olympian fencer, choreographed pretty much all of the significant sword fights in the sci-fi or fantasy movie realm in the last half to three quarters of the 20th century. Highlander, Princess Bride, Mask of Zorro, Lord of the Rings, Three Musketeers, pretty much any time you were enthralled by a sword duel on screen in a film from about 1975 - 2010 or so, it was Bob who made it happen and who trained the actors to make it look good. I'm hoping C.C. Smiff, who swordmastered some Game of Thrones and the Force Awakens duel, comes up to similar standards someday.