Niko is a very kind and caring kid

 Being the messiah that the prophecy had foretold, they became determined to reach the Tower and bring the sun back to it in order to save the World, even despite various other people stating that the sun won't stop the World from dying. Niko is also helpful, which is shown when they repair the Rowbot at the dock in the Barrens, and volunteer to find Alula and return her to Calamus in the Glen.

Niko has been stated by Eliza to have an ambiguous gender