Venerable Tusa arguably piloted the weakest expert mech of the Larkinson Army.
That did not discourage him at all. Instead, his lack of contributions in the last few battles spurred him on to work harder to develop ways to exceed his limitations.
This was how expert pilots were like.
Fortunately for Tusa, he made a lot of progress. He not only discovered that the Shadow Dance Dagger Style became a lot more effective with the addition of exotic radiation, but also found that his companion spirit could complement his actions!
Blackwing was an extension of himself. Imbuing him into a specific mech part enabled Tusa to resonate with it a lot more than before.
This was a trick that every expert pilot with a companion spirit had come to learn, but that was only a shallow method.
What truly enabled Tusa to draw out Blackwing's potential was when he performed a Shadow Dance!
