During The Last War Decker was a sailor in the navy. Mordan spoke highly of his navigation skills. After his naval career he joined House Lyrandar working aboard a elemental galleon. House Lyrandar taught him how to speak Aquan so that he could communicate with the ship's water elemental. During the nights when the rest of the crew were asleep he use to converse with the elemental and upon learning of how the elemental felt about being captured he decided to never enslave anything living. It is not detailed in the book but when Decker is first approached by Vedykar Mordan he acts hostile to him and is unwilling to help. It is stated that Mordan wronged Decker on a previous job.
Decker has an Iron Defender named Fang though according to the Eberron Campaign Setting p.287 an Iron Defender is created using a pint of the creator's blood though Warforged are constructs and have no blood.