The Dragon's Den (竜洞; Ryuu Dou) is a location in Suikoden.
It is a cave passage linking the Kunan region to the Dragon Knight's Domain. Mathiu suggests that Tir and Humphrey travel to the Dragon's Den to gain the cooperation of the Dragon Knights, led by Joshua Levenheit, Commander of the Knights of the Dragon's Den. When they are denied access, the party heads back to Antei, where they meet Vincent de Boule, who reveals a secret entrance to the Dragon's Den.
At the end of the tunnel near the Dragon Knights' Fortress entrance, is a large chamber, home to several sleeping dragons. It is revealed later that these dragons had been poisoned with a sleeping potion by Windy, and a necessary antidote would have to be concocted before Tir could get the total cooperation of Joshua and his Dragon Knights. Eventually, the three ingredients for the antidote were assembled and doctor Liukan produced the antidote and managed to successfully awake them, the dragons then provided assistance near the end of the war.