During the Principality of Zeon's race to develop a superior fighting machine, four prototype mobile suits were developed from different engineering companies: one of these was Zimmad's EMS-04 Zudah. It had a good power plant with unprecedented thrust and acceleration. It also adopted a prototype engine known as the Jupiter engine which was based on Zimmad's prototype Mercury engine. However, this prototype engine had a fatal flaw - if it was overexerted, the suit would overload and break apart. Zeonic Company used this information to outdo the Zudah with their YMS-05 Zaku and successfully marketed the Zaku series.
Despite its flaw, the Zudah was later resurrected under the model number EMS-10, with some minor improvements and cosmetic differences. Its left shoulder was fitted with a movable shield that could be swung to the back, and this shield is also equipped spikes for melee combat. The EMS-10 was said to be fitted with the improved "Saturn" engine, previously used on the MS-09R Rick Dom (though whether this is true or merely propaganda is unknown). It could also use the Zaku series' weapons and a new 135mm anti-ship rifle. However, despite these improvements, the suit was still prone to breaking apart from overexertion.