Dune
Do I need control of a discovery location to use it, and can Fremen ride a worm there?
You only need forces in the location (occupying it) to use its ability; control isn't required. The Ecaz & Moritani rulebook does cap a revealed location at two factions, and the location is immune to storm and worms. Players agree Fremen may ride a worm into one, since only the ending territory matters.