Therefore, according to the current cultivation world, or at least according to the calculations of the lineage of the Mountain Master, one only truly 'casts off the mortal coil and steps onto the path, beginning the quest for the Dao' after reaching the Nascent Soul Realm. It's no wonder, then.
In fact, the original plan of the Xuantian Sword Intent was for Li Fan to switch to practicing the superior techniques of the Beichen Sect at the Golden Core Stage, cultivating the Sword Embryo and Sword Infant, and then directly transforming into the Sword Heart and Sword Spirit.
However, the Daoist methods brought out by Lou Guandao were not inferior, and the cultivation from the Golden Core to the Nascent Soul was still at the stage of laying a foundation. The key difference lies in the secret techniques for nurturing the Golden Core into a Nascent Soul, which are distinct from one another.