Evann using his Elemental Powers
Rangers are people with the power to command the Elemental Force, which flows through the Geo Stream of the world. Rangers can use their powers to open up portals called "Geo Gates" - these gates allow people to travel instantly from place to place.
Evann and the Ranger found in Locca are the only known Rangers in the game. Evann's father was also a Ranger, before he passed away prior to the events of the story. Their ranks are apparently scarce in number as the Nortis Army goes out of their way to hire Evann (considered to be an inexperienced Ranger), even after he repeatedly ignores their contact.