Pendragon series

Bobby finds himself in the territory of Cloral, a world entirely covered by water, which is nearing a huge disaster. He learns that it is up to him to help rid the area of marauders and locate the legendary lost land of Faar, which may hold the key to Cloral's survival.

In his ongoing battle to save Earth and its parallel worlds from the demon Saint Dane, fifteen-year-old Bobby Pendragon travels to Veelox, a world whose inhabitants have abandoned their real lives in favor of virtual reality.

Taking advantage of a severe drought and the long-standing distrust between two tribes, the demonic Saint Dane attempts to take over Loor's home planet of Zadaa, opposed once again by the teenaged Pendragon and other Travelers.

With Saint Dane seemingly on the verge of toppling all of the territories, Pendragon and Courtney set out to rescue Mark and find themselves traveling--and battling--their way through different worlds as they try to save all of Halla.

Each of the Travelers returns home to learn the truth about their origins before being reunited for a final, inevitable confrontation with Saint Dane, whose efforts to control Halla are destroying its very foundations.