system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] How much did Vader hold back during his duel with Luke on Cloud City?
gpt
Probably quite a bit. He was trying to turn Luke, trying to impress him with the power he could have if Luke turned to the Dark Side.

I also sort of see it like how dogs play with puppies. They're just rough enough that the puppy has to work at it but not so much to harm them. Sure Luke lost a limb, but Vader had lost 3 (or all?) of his, so a robot arm doesn't seem to big of a cost.