Noble directly below War Hero (In rank, not position)
Nikos is a short muscular Nobleman. He sent the messenger to get you after the mishap in Impiltur that tarnished your rep. His messenger paid for passage to Chessenta. Nikos is a high ranking noble, right below the War Hero of Chessenta herself.
Nikos asked you to find the Green Hand Killer and stop him, and also keep the peace in Luthcheq. He offered, as a reward, 5,000gp each and each an item from his personal armory or his contacts of a value roughly 25,000 max.
You do also remember (because I just remembered) that his servant stopped you from going in one area of the mansion in favor of a different route. You got the feeling he was trying to avoid something.