Strongest Descending Step
Raze was unable to progress further with his Dark Edge Sword Arts, unable to learn the 5th to the 8th forms in the book. There was something lacking, and Raze most likely felt it was his Pagna Qi.
He needed to be a higher-level warrior, or either increase his magic power and pool to make up for his lack of Qi, and then maybe he could somehow perform the final steps.
However, as Raze grew stronger, it became harder for him to advance further. He was a five-star mage, and the best power stones that could help him progress were nearly impossible to come by unless he ventured into higher-level portals and fought against a Dimension boss.
He was now a middle-stage warrior, so extracting Qi from regular middle-stage warriors didn't give him the shortcut it once did. Cultivating like everyone else would take too long.
The dangers of Pagna were increasing, and he would be long dead if he relied solely on conventional methods.