This machine is based on one of the three Gundam mk-IIs captured by AEUG at the start of the Gryps War and sent to Anaheim Electronics for research purposes. It is a redesign of the Epsilon Gundam, which was conceived by Anaheim Electronics as a successor to the mk-II, which had been initially feared to lack performance. The design concept of the original Epsilon Gundam was largely a cross between the mk-II and the Z Gundam, and it aimed to be a machine that was both heavily armed and highly mobile, but the original technology made it difficult to complete the Gundarium ε and nuclear pulse propulsion systems, and it was not suitable for immediate combat in wartime.

RX-178 [ε] Gundam mk-II [Epsy] | ラルフ's Gunpla works