Open World is an ability that allows Ban Sihyeon to transform his Dungeon into a dimension totally disconnected from the outside world that takes the form of a beautiful green pasture right out of fantasy stories, so whatever happens inside will not affect the outside world, while those hiding inside will be safe from any calamity befalling the outside world. Only those invited by Ban Sihyeon are allowed in, and on the outside a Barrier is erected to prevent entry.