When Miskit and Cogsley were taken by a Wyvern and dropped into its nest, one of the eggs inside hatched and immediately assumed the two were its parents. When Vigo's helicopter arrived to rescue the stranded robots, Cogsley shoved the Wyvern out of its nest to save it and the infant instinctively learned how to fly.
Miskit and Cogsley left with Vigo Light, and the two took refuge in Vigo's shack on a nearby strip of land, while the Wyvern continued to follow them. When they finally left with Vigo, Cogsley decided to keep the baby as a pet and named him Dagno. Since his adoption, Dagno has rarely left Cogsley's side. In Firelight, when Cogsley is kidnapped by Gabilan, Dagno steals Cogley's helmet and get's the attention of Enzo and Rico. When Rico sends Dagno to go get help, Dagno instead doubles back and slams into Gabilans head, knocking them both unconscious. He is later seen being held by Rico in a pink blanket or towel with a bump on his head.
- Dagno is very similar to a character named Bartleby in Jeff Smith's Bone; Both are infants of a dangerous or despised species that are taken in as an ally by a member of the supporting cast – that being Cogsley and Smiley Bone. Also, both Miskit and Fone Bone are wary of taking the creatures in.
- Dagno was named after Kazu's son, Juni's first word.