Glorifyd
Legend
He suffered his injures at the hands of Obiwan. Obiwan cut his legs off on Mustafar. That was when Vader was put in his armored suit and given his breathing apparatus by Palpatine. I literally grew up on this Star Wars sh!t. I was just a elementary school youngin' when A New Hope came out.
Much to learn, have you. Understanding the point, you did not.
I guess you havent seen Rogue One yet? Darth Vader is smooth and crisp in the last scene. Its scary good. Rogue One ends SECONDS before Episode 4 begins. Darth Vader changes to a clunky old robot when he fights. Nothing has changed to Darth Vader in that time.