"The mind is the precursor, the way, and the end." That was the name of the technique he chose. It matched his thoughts perfectly and carried an air of mystery unique to Kayden. This technique was based on using your path as the sole basis for your advancement. Within your mind, you should be able to consolidate your path in an immaterial way.
Their cores would continue to function normally and advance to the fifth realm with increased strength, but they would no longer be the main part of their structure; your mind would be. Everything would revolve around his path. It was perfect for Kayden, but the technique had some ridiculously bad downsides. Any insecurity about his path would eventually kill him, no matter if it was during the advancement or years later.