Board Thread:Dark Souls III/@comment-3236835-20160805064715/@comment-29522860-20160807230506

He might simply be the most recent Unkindled (before the Ashen One) that had to force Lords of Cinder to return to their thrones. I believe this because he is seen in the opening cutscene, dragging a body towards the thrones in the shrine, and undergoing the endgame ritual where the handmaiden sprinkles the cinders on you.

Which might mean that he was the last person to link the fire before the absconded lords. That's  just my theory.