The Pure Lotus School is a quasi-Imperial Lineage; it was created during the Desolate Expansion Era[note 1] by a friend of Immortal Emperor Yan Wu. They have a deep relationship, so Yan Wu left part of his legacy in the School. Thanks to that, Pure Lotus School is considered to be an Imperial Lineage.
The Pure Lotus School was also affected by Immortal Emperor Yan Wu's character, so they didn't want to interfere with worldly affairs. The School created the Southern Tang nation to take their place in governing the world.
Ye Chuyun was the Prime Disciple of the Pure Lotus School. After obtaining some great creation from the World Tree she quickly reached the Virtuous Paragon level and became the Sect Master of the Pure Lotus School as well as the Royal Lord of the Southern Tang.