This allows you to use a special character and that character's weapon.

This hostess was chosen to join the fight from "Dream Club," a club for adults that can only be joined by those with a pure heart. The most aloof hostess at Dream Club, Mian appears to have reluctantly agreed to help defend the Earth. Always depending on others, for her Ability she sets down an automated laser turret, and for her SP Move she requests an explosive shooting star attack. For her weapon, she uses a devastating laser cannon that appeared in the EDF: IR world. The longer you fire it, the stronger it gets, and at maximum output it can deliver some ruinous results. Now, THIS is pure power.

More details on the official game page of Hostess Mian from Dream Club, Giving the EDF a Try!? ...