Ensign Niko was the identity assumed by a Harvongian shape-changer who lived during the 2370s. During this time, he posed as a male Human Starfleet command division junior officer, and served aboard the USS Quito.
Niko was a close friend to Beckett Mariner. His true nature was seemingly triggered after one day Mariner joked that he was one. Niko was last remembered by Mariner being phasered by the Quito crew after killing his girlfriend Angie. (LD: "Cupid's Errant Arrow")