The Ylimaf and the Sacred Key by J. L. Smith
On an Island called Noitacav there were simple people called the Ylimaf. The Ylimaf live under a force field for protection from an evil sorcerer. Twin teenage boys, Relyt and Nivram and Princess Nnylyks learn of a possible infiltration of their protective force field and learn of a way outside of their enclosure to go on pursuit for the Sacred Key that will protect them all. They go on a great journey and meet fantastic striking Fairies, a talking rock caterpillar a stunning Annekam, and massive Ydal Gubs and so many more. They also combat horrendous Trolls, giant Orcs and a wicked, foul sprite. They venture through an island only their parents have known. Climb and scavenge through a crumbling castle and travel through glowing mountains that haven't seen a human in ages. During their Journey they encounter challenges and issues but make many lifelong friends along the way. Their adventure doesn't go the way they plan and the biggest shock is yet to come. They believe they have finally outwitted the evil Semaj but have they really?