The Custom Lancer is an upgraded version of the Mark 2 Lancer Assault Rifle made by Marcus Fenix with several design changes, such as a more angular positioned magazine without a lock well, a slightly longer barrel, extra affiliation lights placed around the weapon, a more rearward ejection port, a wooden stock, and a flashlight attached to the right of the barrel. Like its predecessor, it has an integrated Chainsaw Bayonet. Marcus' modifications were adopted by the Coalition of Ordered Governments and put into production in 42 A.E. as the Mark 3 Lancer Assault Rifle, which replaced the Mark 2 model as the standard issue rifle of the COG Army.
The Custom Lancer is a legendary weapon skin for the Mark 2 Lancer Assault Rifle. Like the Mark 2, it can only carry 50 rounds and hold a maximum of 500. The flashlight is not included.