Darth Ruin Creation

Darth Ruin as a very significant and powerful sith from history but he has had almost zero exposure, he is supposedly a powerful sorcerer that used to be a jedi and he is extremely selfish but aside from that not much is know about him...
If you were to flush out his character how would you make him?
What do you think Darth Ruins force powers, Lightsaber skill level/style, and story be?

I might make a speculation thread for him.