Dragon's Crown
ドラゴンズクラウン
The manga is set primarily in the Kingdom of Hydeland and revolves around a legendary relic, the titular Dragon's Crown, and the quest to retrieve it. A mysterious coven of magic-users with influence in even the highest levels of government seek the treasure and have used their sorcery to link long-forgotten ruins, dangerous labyrinths, and many other areas together in order to search for it.
Note: includes a bonus epilogue chapter.