I'm looking for the title of a book, its details are:
- Children's book series.
- All people live on an island surrounded by fog.
- Boy is chosen to be trained as a magician and is picked to be trained by the head of the guild.
- Magicians use magic by casting rune magic, wither by formation of the hands into the symbols or drawing them inside a formation.
- Upon graduation, magicians are chosen to enact a spell to travel to the other world, where magic still works but is different.
- There are orcs and people, and I think I remember goblins of some sort living underground, both in that other world and on the island!
- In that world, there is a main bad guy, who everyone is afraid of.
- It turns out that main bad guy is actually the head of the guild in disguise.
- The boy battles him and sends him up into the stars.
What is the name if this book?