The Dragon God is, according to Hieda no Akyuu's account in Perfect Memento in Strict Sense, the highest god of Gensokyo. According to that same account, the dragon looks like a serpent with hands and horns and that is thicker than a great tree that's thousands of years old, and is so long that it can block out the sky. Co-creator of Gensokyo alongside Yakumo Yukari and the other Youkai Sages, but it has not been seen since it assisted Yukari with constructing the Great Hakurei Barrier.
Hakurei Shrine is generally attributed to the Dragon God by fans, since it is the nexus point of the Great Hakurei Barrier they helped create, but there is no concrete evidence in canon.
Might be based on the mythological Ryūjin, dragon-god of the ocean and storms, though more canonical information points towards Tenryuu, the celestial dragon of the Big Dipper, which would also give it a connection to Matara Okina.
