Lani's purpose can be traced back to the beginning of this world.
As per what Mistelina had earlier discussed, the initial part doesn't surprise much. At that time, this underground world was enveloped in flames, where all life merged as one. Then — the Golden Tree appeared, separating the flame, and subsequently various types of life were born into this world.
However, from this point, Lani's narration completely deviates from what Mistelina described.
According to Mistelina, the Golden Tree was born from the furnace flames, a deity protecting this land, hence they revered it as the "Mother of the Earth".
Yet, Lani told Duanmu Huai that this wasn't merely a coincidence. In fact, the emergence of life from the furnace was caused by an external force.
They call it the — Supreme Will.
According to Lani, initially, the Supreme Will sent a meteor made of gold and a wild beast to the Borderland, accompanied by a representative of the Supreme Will — a finger.