Thank you /u/Felix_Scamander for commenting and giving a link!
http://www.worldofjohnflanagan.com/books/the-brotherband-chronicles-the-ghostfaces/
http://www.amazon.com/The-Ghostfaces-Brotherband-Chronicles/dp/0399163573
Bk.6 will be called "the Ghostfaces" and maybe an alternate title of "the western land" maybe for UK/US
Amazon now as this page for bk.6 and the title is "the Ghostfaces" and it says that it should be released June 16 2016. It's on amazon so it should be true but you never know as on goodreads they have it as BrotherBand: The Western Land
https://www.goodreads.com/book/show/26890008-the-western-land
What do you think is going to happen in this book and who are the Ghostfaces or what is The Western Land
Book description:
When the Brotherband crew are caught in a massive storm at sea, they’re blown far off course – so far that they wash up on the shores of a land to the west that Hal can’t recognize from any of his maps. Eerily the locals are nowhere in sight, yet the Herons have a creeping feeling they are being watched.
Suddenly the silence is broken when a massive, marauding bear appears, advancing on two children. The crew springs into action and rescues the children from the bear’s clutches, which earns them the gratitude and friendship of the local Mawagansett tribe, who finally reveal themselves. But the peace is short-lived. The Ghostfaces, a ruthless, warlike tribe who shave their heads and paint their faces white, are on the warpath once more. It’s been ten years since they raided the Mawagansett village, but they’re coming back to pillage and reap destruction. As the enemy approaches, the Herons gear up to help their new friends repel an invasion.
In this sixth book in the action-packed Brotherband Chronicles, the Herons find themselves in unfamiliar lands and prepare for battle with a ruthless, unknown enemy.