I was going to say Darkseid, and he's definitely up there. But I thought: "Wait. He's the god of tyranny. Of course he's going to be a douche, it's his job description and indeed his very being." So, I'm gonna single out someone else.
I'm going to call out Professor Charles Xavier. His contingency kill plans for all the X-men, his using his powers on his brother, his failure to deal with his own psyche which resulted in Onslaught, the whole vulcan situation, his actions as a member of the illuminati, his HUGE need to keep everything secret and practically sabotaging his own team.....
yeah, he's a douche. 👇 He didn't use to be, but over time, he's turned into a magnificent douchebag, instead of this great humanitarian, the mutant mandela (as I'm reasonably sure he was perceived at one time.) He's not the man we thought he was, and whether it's poor writing or not, he's a douche.