The Battle Agency is a new way of battling. It is similar to the Battle Factory from previous Battle Frontiers in that you use rental Pokemon, but this time with a twist!
You can start playing in the Battle Agency as soon as you have beat Sophocles’ trial at the Hokulani Observatory. Simply talk to the woman on the right inside your Festival Plaza castle. You can’t miss her. Behind her is a backdrop showing various Pokemon sprites with lots of cool looking hexagons.
When you win in the Battle Agency, you don’t get BP unfortunately. But you do get a boatload of FC instead, which can be useful if you are trying to use the Rare Kitchen to level your Pokemon up quickly, or are otherwise farming for facilities of some sort.