Robotech: Expeditionary Force Marines Sourcebook One is a Palladium Books roleplaying game guide released in 2015. It adds new background for the Pioneer Expedition/Sentinels, adding new mecha and equipment and takes place after the start of the Fourth Robotech War. The new equipment comes from concept artwork from Robotech II: The Sentinels, Genesis Climber MOSPEADA, and Robotech: Invasion (video game). The book also profiles the Invid forces under The Regent and the Sentinels races.