Kes was an Ocompan?, a race native to the delta quadrant. She was taken into the /Voyager crew with her partner, /Neelix?. Kes has mysterious metaphysical? powers that were relatively unknown, even to herself.
Kes developed a close relationship with /The Doctor during her time as an assistant medical technician.
She left the Voyager crew when she "evolved" into a different state, but before she left she threw Voyager 20 years closer to Earth.