A Delta Quadrant people most of whom dismiss the cloaked Ba'neth as a myth, apart from an investigator who helps Voyager after Tuvok is attacked in Riddles.
The Kesat appear in the Voyager episode Riddles. Their space borders that of the Ba'neth, a xenophobic species who hide themselves and their ships behind cloaks. So few have ever glimpsed them that Kesat officialdom treats the Ba'neth as a legend.
In 2376 Tuvok is shot by an invisible intruder aboard the Delta Flyer on the way back from a diplomatic mission to the Kesat, and suffers serious neurological damage. Naroq, a deputy investigator with the Kesat security service, comes aboard. He has spent years gathering evidence that the Ba'neth exist and has built a photolytic converter to expose them.
With his help Voyager locates a Ba'neth fleet, and Janeway trades scan data for information about the weapon so that the Doctor can treat Tuvok. Naroq gives up his own detection technology to close the bargain.