The Mechanized Assault Unit, or MAU, is the single most powerful weapon on the battlefield of the 33rd Century. The first true MAU - the Spirit Light MAU - was developed by the Calandrian Empire in 2523 AD. The concept quickly spread throughout the galaxy. The MAU was not the first battle walker ever to grace the battlefield (the Atlantians had used battle walkers for centuries), but it was the first truly effective one.