The tail slam would have shown everyone the massive strength that came from the control that Onyx had trained. However, General Marshal was unaffected. He casually changed stance before slamming his tower shield forward. Onyx was pushed back slightly.
"I see, you are much heavier than you appear to be. Is it your body, or the armor?" The general was fairly impressed by the attack though. He had felt the attempt to stun him in to falling. If he had, he would have had a very hard time blocking a following attack.
Onyx brought his tail up again to slam it down toward the general, however, this time instead of a ground shaking slam there were small blades of shadow that formed beneath Onyx's tail. He had used his tail to create a longer shadow that hid his true intentions. It was a wise move that many had not expected.