Cascade is a planet in Sonic X. In the Japanese version, it had no name.
Cascade was once a beautiful planet. However, one day the Metarex came and took the Planet Egg, causing the planet to die. A Resistance fought Pale Bayleaf, in hope to make Cascade beautiful again. Two of the Cascade Resistance were Molly and Leon.
Later, Dr. Eggman arrived during a fight and Shadow saved Molly, causing her to believe he was the spirit of Black Wind. However, her hope vanished when Leon and several of the Resistance gave up. Molly was killed by Bayleaf (in the Japanese version; in the English version, she is said to have left Cascade and seemingly disappeared) and Shadow, using the power of the white Chaos Emerald, got revenge by smashing Bayleaf's ship.
After the Metarex's destruction, the Planet Egg returned to the Planet, making it beautiful once again. Shadow built a grave to Molly using debris and gave Rouge the Chaos Emerald, leaving them to fight the Metarex alone. In the Japanese version of episode 78, Shadow was seen coming back and placing a rose on Molly's grave.