I donít know but I think that maybe the next Darth Traya could be Brianna (The Handmaiden).... She was betrayed by Atris , she is part of the New raising order and she cant control her emotion very well So she is my number 1 option....
if is not her then
Or if is not her for last I think It will be Dustil
He thought that heís father betrayed him but then he "Forgave himĒ but then remember he did not decided to walk the path of a Jedi , he just leaved , where? We donít know and remember he was a Sith and trained in the ways of the dark side... so he is my 3 and final option ....
"Evil is a word used by the ignorant and the weak. The dark side is about survival. It's about unleashing your inner power. It glorifies the strength of the individual."