MechaArthur is the result of rudimentary cloning efforts of the North Korean government in the late 1940s. He is derived from skin scrapings of the original MacArthur, who had been placed into crygenic stasis by the American military, due to his volatility in peacetime (were MacArthur not cryogenically frozen, experts project that he would've continued his advance into the Japanese Arichipelago indefinitely, eventually circumnavigating the earth and attacking the Eastern Seaboard).
MechaArthur is in many respects similar to the original, but was modified slightly to suit the North Koreans' interests. One major alteration is his programming; while Douglas MacArthur was designed for lateral (across longitudinal lines) conquest, MechArthur was programmed to attack omnidirectionally. While this proved effective in gaining control of the Korean landmass and part of Manchuria, it also resulted in numerous drownings as North Korean shocktroops attempted to subdue the Bay of China and the Sea of Japan.
MechaArthur was also augmented with mechanical improvements that were, at the time, state-of-the-art. However, as this was pre-1960, North Korea had not yet gone through its Industrial Revolution, which meant that MechaArthur possessed such technological wonders as a broze corncob pipe and glowing red eyes powered by candles. MechaArthur would be the subject of ridicule among many International conferences.
While effective in the intial advance during the Korean War, MechaArthur was ineffective in holding the peninsula for long. While made in the image of MacArthur, MechaArthur was no match for the original military automaton, and he was driven back north to the disappointment of then North Korean Leader, Kim Il-Sung. "I shall return," MechaArthur proclaimed. He was never seen again.
It is thought, however, that MechaArthur still exists; Il-Sung, in his shame, most likely sealed MechaArthur in a secure bunker in Pyongyang. Whether the clone is still combat-operational is a question that remains unanswered, but some sources claim that North Korea is attempting to refit the original robot-man with a modern nuclear reactor, thus removing the need to fuel MechaArthur with the conventional fuels of chewed cigar butts and the souls of buck privates.