The Changing Armor System (CAS, see Naming for more) is a system where the armor of a Zoid is removed and replaced with a different module. This gives the Zoid a heightened ability to adapt to multiple different situations. A Zoid with Fuzor partner(s) is distinct to a Zoid with CAS units, as a Fuzor Zoid is able to operate independently of the main Zoid, while CAS unit is only a set of armor, and thus must be mounted to a Zoid to be of any use. The Liger Zero and Berserk Fury are the two Zoids that most heavily utilise the Changing Armor System.