Rivertown Gorge is Kali's fortress. Technically the fortress is inside the gorge, but it is the only thing there that you can reach, so they are the same thing.
All the generators need to be destroyed in human form. Double check all the platforms in the northern section to find the one(s) that you missed. When in human form, check the mini-map for red dots that would indicate opponents nearby, possibly above or below the current platform, so maybe a section you missed which could have a generator.
