I wonder if this has been covered, I've not seen anything, so I thought I'd ask.
I was under the impression that legendary drops were RNG, and that legendary characters who drop the drops were determined on what skill level you are, and I am not convinced this is the case.
I've done a bit of save scumming on legendary drops, and at least in my game, they don't appear to be RNG, but fixed.
I have also noticed that, despite difficulty levels, legendary characters spawn in the same places for different people running different difficulties.
Can anyone confirm or prove this wrong?