Donko is very quick, and he uses his superior speed to run and help both Kajika and Isaza in exchange for money. At first, he seems very greedy but in fact he is very nice. He wants to gather enough money in order to buy an airplane and travel where he wants whenever he wants. He is also a skilled mechanician.
Donko meets Kajika after seeing him defeating thugs in a village and tells him that the world-famous assassin Isaza is after him and is also in the village. He then helps Isaza to find Kajika in the desert for 100,000 Dons twice, and hides during their confrontation. After Kajika is knocked out by Isaza, Donko tells Gigi he will retrieve the egg Isaza took from them, in exchange for 1,000,000 Dons. Donko finds Isaza in the desert and repairs his airplane. He then steals the egg and brings it back to Kajika.
When the egg finally hatches, Donko helps Kajika find food for it. Soon, Gibachi's men manage to wound the young dragon and Gibachi drinks its blood, which turns him into a powerful dragon-man, but Kajika manages to defeat Gibachi. After this, Isaza gives his airplane to Donko in exchange for Donko to drive him to the hospital.