Niko is a young commoner boy, with scruffy light hair falling to the sides of his face that partially covers his forehead. His robes are a little tatty and he wears a large bell cap which seems a little too big for him. He also carries a Beherit which is later revealed to be destined for Balzac.
He is a simple-minded and cheerful boy.
Some villagers once teased him and beat him. He died, hungry and alone, one winter night near Eriza's church; she couldn't hear him due to the heavy blizzard storm.
When Guts rushes toward Eriza's church, he finds out that Niko is now the Heart of the Great Tree, and has to deal with both Eriza and Niko. After the fight, and seeing how Gyove and his armies were attacking the village in which Niko once lived, a still living Eriza throws herself to the flames whilst carrying the remains of Niko's torso -the only remaining human part of his.
- He resembles Nico from the Berserk manga, though it is unclear if they are intended to be the same character.