During the events of FusionFall, the Providence HQ was converted to a place to train new kids to fight in the war against Fuse.
FusionFall: The Story of Pike Aftershock
In "Fusion Fall: The Story of Pike Aftershock," the Providence HQ is where all students were transferred after their first semester at the Fusion Fall Academy. Instead of having separate classes, students here would simply be instructed to defeat thirty Fusion monsters, after which they would be allowed to do as they please. Only three staff members were revealed at this point:
Finn - Dorm Adviser from A-N
Rex - Dorm Adviser from N-Z
Ash Ketchum - Guidance Counselor