Marine Corporals are the pilots for the Speeder MK I "Raptor" Vehicle in the Acid Rain World, they are the only known ranked soldiers. This position may have been earned through their knowledge of the Raptor, the ability to operate as a scout, anti-personnel unit or together in squads of 3's as a fast defence protecting the slow ST-1 Strongholds. The rank may also be related to their expertise operating such a dangerous and lightly armoured vehicle.
As MK I's are used by the 303rd division, Marine Corporal pilots are considered Marine soldiers.
The figure uses the existing Acid Rain World figure buck but has original armour, helmet, camouflaged legs and a gas mask painted with a ghoulish skull face (implying a sense of daredevil bravado). The Marine Corporal has no hand weapon suggesting that these soldiers rely solely on the Raptor's chain-gun for firepower. There is a hole in figures' lower back normally used for an attachment which was not included with the release.
Marine Corporals were available for general sale in August 2014 along with the Raptor. An alternative version "Red Face" was released as an exclusive at the Hong Kong Toy Fair in Dec 2014.