What it takes to be a Spirt Master
There are Spirit Masters and those who call themselves Soul Cultivators. In cultivation, spirit masters can be considered perfect elementalist that has complete control of their souls.
They have an in-depth understanding of how the soul works and how to manipulate it in ways that will benefit them. They have total control of how the soul works, how to tweak it, how to channel it, and even how to enhance it.
Soul cultivators are just people with somehow robust souls that can accommodate them when it comes to using techniques and abilities that require the soul to work. They don't have any understanding of how the soul works. Their only advantage is how to use soul-related abilities.
But spirit masters are different. A true spirit master exists on two planes. They have the physical plane and the spiritual plane (Astra Realm). They exist in two planes simultaneously. But in most cases, not many spirit masters can see the spiritual plane.