Story from the ROSE Online wesite
"There are various tales, fantasies, and legends around the seven planets and many of them contain some grain of truth. Our universe, or as it was called in the old tales, the 'Sea of Souls', was a vast ocean of darkness until the goddess Arua created the seven planets. Each one of them was special and unique. However, all seven planets were created with Arua's love and they shined with the brilliance of seven stars, filling the vast ocean of darkness with wondrous light and life. However, Hebarn, god of malice, grew envious of Arua for her creative power. He forcefully took the seventh planet and pompously named it after himself. Hebarn had become a constant threat to the peace of the seven planets as well as to the goddess Arua. To protect the planets from Hebarn's looming menace, Arua created the Visitors, living beings to protect and inhabit the planets. They were scattered among the seven planets to bring peace and justice to the different worlds."
The seven planets of the world of ROSE Online were created by the goddess Arua. However, Hebarn, the god of malice, took over the seventh planet and renamed it after himself.
To protect the other planets from Hebarn, Arua created the Visitors and sent them to Junon, the first planet.
As stated from the story above, there are seven planets and currently only four are accessible. Each planet has currently one major city (with the exception of Junon which has two). It can be speculated that the last three planets will be released in due time.
Four planets are currently accessible:
Three are currently unreleased: