“Here be dragons” (Latin: hic sunt dracones) means dangerous or unexplored territories, in imitation of a medieval practice of putting illustrations of dragons, sea monsters and other mythological creatures on uncharted areas of maps where potential dangers were thought to exist.
Elden Ring used these originally. Over time, though, as they fixed and changed parts of the map to reflect the in-game geometry more, they also removed some of the “dragons” decorating the map. IDK why. Best guess is that they simply reverted to older maps during development before the dragons were added and didn’t put those back in because they’re not exactly necessary or important.