Kokoro lived in Satellite, with a number of other young children, including Taiga, Ginga, Daichi and Hikari. They were often visited by Crow, who gave them Duel Monsters cards and advised them not to get in trouble with Sector Security.
Kokoro was absorbed by the black fog when it released on Satellite. This was used to Summon the Earthbound Immortals. Crow managed to survive the black mist and for a brief moment thought the children did too. He saw some of them including Kokoro run towards him, before realizing that it was just his imagination.
Kokoro was released after the Earthbound Immortal, she had been sacrificed to Summon, was defeated.
- Yu-Gi-Oh! 5D's episode 30: "Fight or Flight"
- Yu-Gi-Oh! 5D's episode 32: "Dark Signs, Part 1"
- Yu-Gi-Oh! 5D's episode 51: "A Whale of a Ride, Part 1"
- Yu-Gi-Oh! 5D's episode 68: "Trash Talk"
- Yu-Gi-Oh! 5D's episode 137: "An Approaching Terror - The Citadel of God, Ark Cradle"