Categorized as a prototype attack-use mobile suit, the MSA-004K Nemo III is an improved armament version of the MSA-004 Nemo II and can function as a fire support unit. Its firepower is greatly enhanced with the addition of a large beam cannon on the backpack, powered by tank-like E-packs. Besides the beam cannon, the mobile suit is also armed with a beam rifle, a beam saber and 60mm Vulcan guns. Other improvements include enhanced defensive capabilities, better joints, and binder units on the backpack to increase the mobile suit's mobility and maneuverability.
The MSA-004K Nemo III was developed by the Anaheim Electronics for the AEUG based on the MSA-004 Nemo II. However, the death of AEUG's leader, Blex Forer, disrupted communications between the two organizations, leading to the Nemo III's development being delayed. As a result, the first Nemo III was only completed on U.C.0088, January 18, near the end of the Gryps War.