Duko is the eldest sibling and only female Bridge Builder. Despite this, she exhibits a mustache at least as substantial as the male builders. She also wears pink clothes that reveal a rather masculine body. She works exclusively on the Third Continent underground, except for when working on the bridge to the Foreman's Island on Sunshine Seashore.
Duko can be paid to repair bridges in the same was as her siblings, being found on the more recently reached side of the subterranean bridges. She exhibits the same mannerisms as her brothers, specifically pelvic thrusting and meaningless vocalizations, although her voice is slightly higher in pitch.