It was believed that when the race of Oni comes to invade Kyou, Ryuujin no Miko shall arise together with her chosen eight warriors Hachiyou. Ryujin no Miko will together with the help of Hachiyou call forth the Ryuujin--Hakuryu, and  be granted any three wishes the Miko desires.

However, it was not certain whether calling out the Ryuujin may have a special cost...?