What formation is recommended?

he formation you’ll need to choose will depend on the deployed heroes’ class. Mages and support units are usually placed in the backline while tanks and fighters are in the frontline. The only exception for this are certain heroes with semi-hybrid roles like Joan of Arc or Izanami. These support and mage heroes respectively should be in the backline but since their skill sets provide them with more survivability, they can take the frontline slot in case you need them.