Koko is Boko's friend in Final Fantasy V. The two chocobos meet in Pirates' Hideout and have several chocobo babies together. She is first met by the Warriors of Light at the chocobo forest in the Second World, although Bartz states that she cannot be mounted due to her gender.
In the external minigame for Final Fantasy VIII on the PocketStation, Chocobo World, Koko is again Boko's love interest. Their paths first cross during Boko's quest to find MiniMog. Throughout Boko's journey their paths continue to cross until Koko herself is kidnapped by the Demon King, which incites Boko to go and rescue her.
Every time Boko and Koko interact, Boko's power increases, which results in a more powerful chocobo summon.
In the quiz game Brain Blast one of the possible questions refers to Koko: The Yellow Bird is a story about a chocobo living on Gran Pulse. What is the name of the heroine? The answer is "Coco", an alternative spelling of Koko. Tamed chocobos can also be named this alternate spelling.
Koko's name alliterates Boko's. Coco is also the Portuguese word for "Coconut".