Hilda was a religious representative of the God Odin, leader of Asgard (an independent country of Olympus and Sekai, ruled by Odin).
She was in charge of praying for the land of Asgard, continued frozen. However, Julian Solo, controlled by the god Poseidon, possessed during a prayer with the Nibelung ring, making her go into apostasy with Odin, serving Poseidon, which plans to flood the earth and then protect Hilda and his surviving warriors in his new kingdom after the army of Athena be destroyed or when Hilda prove to be useless.
Biography
She declared war on Athena Sanctuary and invades his mansion in Japan, which makes the goddess invade Asgard; there, she learns that Hilda should pray to Odin purchases land not having their melting ice and send a flood to Sekai, and therefore for its invasion and begins to pray to Odin, sending his saints (to find out about the ring, but not who sent it) release Hilda's spell, using the Balmung sword, which can only be achieved with the 7 Odin Sapphires.
Hilda after a fight against Seiya, back to normal and back to worship Odin, saying a prayer that holds the flood. After this, Poseidon decides to act alone, and Athena capture, creating their own flood.