The Soul Sealing Technique, unlike common techniques that used Qi, could only be used if the user could condense mental energy to utilize it. This technique wasn't entirely focused on combat, but at higher levels, it could be problematic. After a slight advancement in this technique, the user would have mental energy at their disposal, just like Qi, not being limited to using mental power only in this technique.
That's why Ruri and the other women could use mental power in different ways. But anything not directly related to the Soul Sealing Technique was crude and not very skillful; the girls had to learn to do everything on their own through trial and error. But now, a technique that used mental power in an entirely different way just appeared.
