Niko

"Niko, to the Rangers."

- Lord Commander Jeor Mormont

Niko is an unidentified background character in the first season. He is a newly made Ranger of the Night's Watch, of the same group of recruits as Jon Snow.

Season 1
Niko is present during the speech Lord Commander Jeor Mormont gave to the "graduating" recruits. Niko is assigned to the Rangers.

In the books
In the A Song of Ice and Fire novels, there's no member of the Night's Watch called Niko.