“The nest of Firstbourne. And in it, your freedom and my power. Come now. Our future awaits.”
Firstbourne's nest is where the Dragon Armor was hidden, and where the Firstbourne and some other dragons reside.
Wu and Iron Baron journeyed there to retrieve the Dragon Armor, but only the former made it out.
The Ultra Dragon's return
After the Ultra Dragon returned to the Realm of Oni and Dragons, it went to Firstbourne's nest.
Wu and Iron Baron enter the nest in search of the Dragon Armor. Wu's dragon blood keeps all of its inhabitants docile. When they find the Armor, Firstbourne encases Iron Baron in molten rock.
The entrance to the nest.