RuneScape’s latest expansion, The Arc brings two new sets of islands for players to explore. The Arc is an area consisting of three islands—Aminishi, an island designed primarily for Slayers, “the trade hub of Waiko,” and Whale’s Maw, “the perfect spot for training your Fishing and Hunter skills.”
More islands are visible on the map and will be added in the future. The Uncharted Isles is a procedurally generated region in which “the really high-level skilling is to be discovered.” It is different every time unless players find an island they like, in which case they can place a flag “to save it as [their] own permanent, private resort.”
You can read more about the islands here or find the full set of patch notes here.
