A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Kyria d'Oreyn
Unless stated otherwise, all information herein is taken from KoD, Ch. 11.
Nathin Sarmain Vendare is the Lord of Maderin. Like most nobles, he is under the Seanchan thumb, and takes suggestions from them as orders.
"The Seanchan said we didn't set enough guards," a stocky fellow about Mat's age put in cheerfully, "and Lord Nathin listens close when the Seanchan talk." (Keilar; Knife of Dreams, Chapter 11).