Exia was created as a high-mobility unit to greatly supplement its close combat role. In order to maximize its potential in speed and movement, its legs was given the best human articulation as possible to improve its Active Mass Balance Auto Control (AMBAC) The trade-off is the reduction of armor parts in several joints that reveal its internal frame; its MS frame is more vulnerable against enemy attacks. However, the pilot can defend against enemy attacks with Exia's GN Shield. It's high mobility design has served Exia well as it has the lowest being-hit rate amongst the four 3rd-generation Gundams.
