Ninjas should return to the middle if there are no enemies on screen that they can target. Also a ninja should help the other ninjas if they have nothing to attack for themselves.
To everyone who has missing saved files. Go get sol editor and just open your saved file then save it without changing anything. It should then show up, you'll have to repeat each time you want it to show up.
 "Ninja and Blind Girl"){kind=icon}
 "Mr Vengeance Act-I"){kind=icon}
 "Kriegs Craft"){kind=icon}
 "MARDEK RPG: Chapter 2"){kind=icon}
 "Parachute Retrospect"){kind=icon}