Byakuya of the Illusions.
Naraku's final incarnation. The only incarnation which lasted any decent amount of time, who also ultimately showed no signs of disobedience. His obedience was never questioned, his subservience assumed by all. No one ever asked him why.
Byakuya, for all his strengths, had one flaw. Due to the nature of his powers, he was fundamentally a cynic. He saw the world as a place of illusion and dreams, none of which proved true. Hope, love, joy, freedom. All temporary whims of the mind, projected into seeming being until they were dashed away, but a breeze able to blow them away, revealing them to be ephemeral, non-existent lies.
Byakuya was a master of dreams and illusions, and he believed such concepts as hope, love, joy and freedom to be but the ultimate projections of his skill. As such, Byakuya refused to hold court with fancies like these, particularly freedom. And so he was, in a convoluted, ultimately depressing sort of way, unable to realise his own true potential or ever escape from Naraku.
Although it was doubtful that this was Naraku's plan to ensure Byakuya's obedience, he found Byakuya's dreary demeanour and easy subservience suitable, and therefore never questioned it, apart from the obvious checking to ensure it was genuine.
And so it was, the tragic, fore-shortened, un-fulfilling existence of Byakuya of the Illusions.