Marco is a merchant of the Erebonian Empire, wanting to do business at the City of Bose. If you talk to him after you are told you can meet with General Morgan during the Missing Airliner quest, he will give you Carnelia - Chapter 3.
Chapter 1 (Missing Airliner pt1): Waiting in the corner at the Bar at Haken Gate.
Chapter 1 (Missing Airliner - After Haken): Near the Bose Market at the east entrance.
Chapter 1 (Missing Airliner - After Nial): In the the Bose Market near Spence's shop.
Chapter 1 (South Block Burglary): In Lucir Orbal Factory in the City of Bose.
Chapter 1 (South Block Burglary - pt 2): Near Katrina's Confectionary in the Bose Market.