Even before the Emperors Era Dark Crow had a certain mission in mind. However, his resources and strength were lacking, so he couldn't carry it out. Only during Immortal Emperor Min Ren's generation had he gathered enough resources and created the last of his Four Legions - the White Crane Legion - specifically for this special mission. Dark Crow appointed Tantai Ruonan as the first commander of the White Crane Legion and Immortal Emperor Min Ren as its chief instructor.
Because of their special mission, the White Crane Legion was the most secretive and elusive legion; it had always been hidden and nameless like hermits even on the first day of its inception. Even other three legions didn't know much about the White Crane Legion. Only the truly loyal confidants of Dark Crow were privy to this information. Some people even believed, that Dark Crow's fourth legion was either Vermilion Legion, Black Dragon Legion, or an imperial legion.