The Spartan 2 is the other new mech coming out of the REF Destroid Combat Systems Laboratory (the other being the Avenger MK-I). It became a reality when the need for a self-dependent artillery support destroid that did not need an escort if necesary. The need arose from reports taken from pilots of the original Spartans and M.A.C.s II and III. They could provide the firepower, but they could be taken out easily be taken out by close-range attacks.
After a study, it was rediscovered that the fire-support mech with the highest survivability rate was the Spartan MK-XIII, or "The Shark", due to a number of short range defense systems, such as the mini-missile launcher and actual hands for hand-to-hand combat. Initially, the R&D team of this project wanted to follow the use of the original humanoid body for the new Spartan. It was then scrapped after one of the engineers saw footage of a Zentraedi Light Artillery Pod from the First Robotech War.
The engineer proposed that the missile launchers should be placed in the shoulders of the destroid, freeing the arms and hands for other uses. The design was somewhat controversial at first, due to the similarties to Zentraedi Battlepods. Some generals even argued that the design would be confusing if visual contact was established. But the test run brought down any doubts that arose in the previous meeting.
The only thing diferent between the original prototype and the actual product is the arms. The original prototype had hands. During a maintenance session, the mechanics working on it did not have an extra set of arms with hands. Then, one of the Bio-Maintenance Engineers proposed the use of weapon arms from an Excaliber which was being repaired. After another combat test, the arms stayed because of the added firepower.