Hello oasis!
You should add a 6th main to the game the one I thought of was based on the land of Iron and how there is 6 battle feilds in the great ninjas war but only 5 mains adding a 6th main to the game would add more flavor and mix things up for people who always have to use the same 5 mains.
the iron main would have the same skills as the other classes with none of the type bootsing skills so it would fit in just fine.
if anyone else can think of something better then I would also like to hear hear how it could be better.