Onmyoji and the samurai of the Sword Pavilion, despite both enhancing their combat strength by concentrating their Guardian Spirits, have different battle styles after reaching the Third Tier due to a slight difference in their approaches.
The samurai place more emphasis on using their own abilities, maximizing their attack power by combining swordsmanship techniques with the capabilities of their Guardian Spirits.
Typically, a samurai's Guardian Spirit acts more like an auxiliary existence, rarely being controlled to directly participate in combat.
By contrast, the Onmyoji's Guardian Spirits possess more spirituality and can actively initiate attacks, or even act as separate entities.
Of course, there is no clear boundary between these two methods. It's just a difference in emphasis due to their different approaches.
This distinction is more apparent at the Low-Tier, but as one's strength increases, the line starts to blur.