He's managed to create a lot of buzz with those vague comments. He is in the limelight exactly as he wishes to be. He has convinced the others that he is doing something BIG and that the secrecy only makes it more dramatic. The others see him in every unknown action and they are all speculating.

As for the more overt forms of attention I'm certain that wherever he is he is living as a King amongst his people.

As to your assessment of his personality, I generally agree with his obvious disdain, but I think it's a surface level bravado thing. Graendal dismissed him early as lesser than Semirhage. Her assessment of him is nearly a joke as she defines someone who in his own mind believed in the greatness of Berid Bel Madir' I could practically see her rolling her eyes. I am sure he was quite accomplished, but I've always believed what Graendal meant when talking about him was more along the lines of how he viewed his own life. Demandred simply got caught up in always finishing runner up to LTT. Graendal and Semirhage were two of the most renowned and famous people of their Age, BBM would have been no higher than they in social standing.

Personally I think his whole demeanor is aimed at impressing the others, thus he openly threatens a man who is a coward, dismisses his weaker ally and beats his chest regarding his unknown achievements. Oh and talks trash about Semirhage when she's not in the room. Given his POV during the Cleansing I see him as a bit of a coward who can't admit it to himself so he puffs up his chest and pretends to be superior and hides behind the line "LTT had everything handed to him, if not for that I would have been the most acclaimed man of the Age" He's sort of like a school yard bully. Picking on the ones clearly weaker and a doing his best to ignore those who may be equal or better than him.

Compare to Graendal, who openly mocks the strongest in the bunch. She's mocked Lanfear, Demandred and Sammael straight to their faces and in front of others! If anything she looks down upon her fellow Forsaken more genuinely than Demandred.