Niko was Roon Osricson's guardian, a shapeshifter who first appeared as a white tiger. He was the leader of the shapeshifters, and as such would remain alive as long as at least one Eternal lived.

Niko could assume many different forms, including a grizzly bear. He pretended to be dead after the Society of the Evening Star raided Roon's castle and massacred his other servants. However, when Bracken and Kendra arrived at the castle, too late to warn Roon of the Society's attack, Niko showed them his abilities to heal his own injuries and change form. He also told Kendra and Bracken to help themselves to weapons.

Later, Niko caught up with, Warren, Bracken, and Kendra to assist them in the battle to try and save Civia's life. He arrived in the form of a bear, but he died when Civia did, as she was the last Eternal.