The Ancient Dragon's Dwelling is the den of the Holy Beast Ragnard. It is located in the north-western most region of Nebel Valley and is hidden by a massive cloud bank. Normally, one cannot reach it without the help of Wilhelm, a mountain man who lives on the eastern side of the valley.
The Ancient Dragon's Dwelling has been the home to Ragnard for many centuries since the time before the Great Collapse.
In S.1182/3, Cassius Bright once paid a visit to Ragnard in its den hoping to challenge it and test his skill with a blade. While the outcome of the fight is unknown, Cassius managed to earn the dragon's trust, respect and friendship. After that battle, Ragnard fell into a 20 year long sleep.
In S.1202, the dwelling was also discovered by Georg Weissmann and Leonhardt from Ouroboros. After awakening and fighting the dragon, the pair took control of the beast with a Gospel device. After having used Ragnard to cause several incidents, Estelle Bright and her party managed to track down the lair and helped saved Ragnard by destroying the Gospel device. Elated to be free, Ragnard apologizes for his actions and make restitution with the group. The dwelling is then abandoned by Ragnard after informing Estelle and co. about the Aureole. It has not been used since.
The structure of the Ancient Dragon's Dwelling is a series of caves with connecting tunnels on the outsides of the caves. Raganard's den is located at the top of the mountain and is more than large enough to hide a beast of Ragnard's size.