I think usually at this time we have been given a hint on Facebook what the next login hero will be, but since we didn't get anything, I am hopeful we will simply get to collect SS for an existing hero ^^ that would be great.
This is either; 1. An old, male support character. Probably a wizard with the ability to heal and shield, or; 2. Something we didn't ask for, such as a female, magical dps or female support like sumiko.