Not much is known about Commander Kross prior to his service with the Earth Defense Fleet. Certain intel notes his work with both FSOG and the Shadow Navy circa 3301. During the early stages of recruitment within the EDF, Victore Beskor himself took note of Kross' varied skill sets. Due to his impressive tactical acumen both in the board room and in the commander's chair, Marcus quickly climbed the ranks in the EDF to become the director of homefront operations. During his time at the helm of Operation Homefront, he carried the EDF to impressive victories until 3305 when he unceremoniously resigned. After being spotted speaking with other Directors and Beskore, he suddenly vanished and went off the grid.

   
    Some intel says that Commander Kross played a leading role in the events leading to the death of Senator Kahina Tijani Loren aka Salomé in 3303. It is speculated that his ties to Federal Intelligence and other Confidential informants led to successfully discovering the location and exact coordinates of Salomé's primary contact Raan Corsen. Corsen was believed to hold sensitive information, including the location of Salomé herself. After requesting aid from the EDF and getting command of several wings of ships he lead the attempt the rescue and apprehension of Corsen. The fugitive was quickly surrounded by EDF forces at an undisclosed land base and ordered to cease and desist, but Corsen immediately made vector for escape from orbit. Despite commanding a ship more than capable of disabling Corsen's craft, EDF brass didn't let anybody fire on Corsen's ship which eventually resulted in him slipping through Kross' fingers. After this event, it is believed that Kross lost faith in EDF leadership, which would eventually lead to his resignation 2 years later. When he was informally asked about this particular incident, Kross stated that he deeply regreted following the hold fire order and not taking the shot to stop Corsen on his tracks. He went on to say that it was a huge loss for both the Federation and the EDF.


    After 2 years of complete inactivity, in early 3307 Commander Kross was spotted in his flagship Redeemer, assisting the EDF with critical operations in Nanomam. After a crushing victory he expressed his desire to wing up with his former allies once again. His security clearances were restored, he was given command of an EDF funded fleet carrier, and thus, Commander Marcus Kross returned to active duty under the banner of the Earth Defense Fleet and the Federation.