Its possible, though I'm not sure how to make a third fairy different enough to be worth
the implementation. I'm sure they could think of something to add some spice and variety
though.

Since they'll need to find ways to add more egi's for smn, the route they could easily take
at cap raise, would be to allow ACN a new summon spell (that would become a new fairy
for sch and a new egi for smn) and allow SMN to learn a summon as well (2 egis with 1 cap
raise)