Auto Guard (オートガード Ōto Gādo)[1] is a Device function that automatically activates a defensive spell (usually of Barrier-type) if its master is under attack but cannot respond due to surprise or injury. It is also referred to as Auto Protection (オートプロテクション Ōto Purotekushon) in The MOVIE 1st.


Subaru Nakajima's Mach Caliber auto-casts Wing Road and Caliber Shot, though whether it is an Auto Guard function is debatable. On the other hand, Mach Caliber displayed the ability to continue fighting even after her master is knocked unconscious.


  1. ^ Auto Guard at the Japanese Nanoha wiki.