If you would like to back up saves to a USB on your PS4, here is how!
You will want to save and exit the game first, as it will prompt you to close the application if you try to do it while it is running.
Backing Up Saves to USB:
Settings>Application Saved Data Management>Saved Data in System Storage>Copy to USB Storage Device>Select Battle Chasers>Select the save>Copy
-To use this feature, you need to have signed in to PlayStation™Network at least once.
-FAT and exFAT formatted USB storage devices are supported.
-Be sure to fully insert the USB storage device into the USB port. Some devices are not compatible due to shape or design.
To Copy a Save from USB back to your System:
Settings>Application Saved Data Management>Saved Data in System Storage>Saved Data on USB Storage Device>Copy to System Storage>Select Battle Chasers>Select Save File>Copy
Note: You need to have signed in at least once with the same account you used when you copied the saved data.