To the great surprise of Jake and Lu Yan, he was not the only one to use this technique. Erwin, who was on the front line not far from him, adopted the same profile stance as Jake when his shield shattered. A yellow aura focused on his exposed side, the arrows hitting him bouncing as if they had struck solid steel.
The former colonel was perfectly calm and already well trained before the Ordeal even began. He probably knew everything there was to know about the Oracle Device, and yet he was there with them instead of elsewhere with the rest of the Earth's army.
Just like Jake earlier, when his shield broke, he picked up a few pieces of his shield relatively intact and threw them like shurikens at the enemy legionaries. The speed of the projectiles was comparable to Jake's and easily broke through the large bronze shields of the enemy's front line, breaking their formation.
It doesn't mean Lu Yan or Erwin don't follow a Path when they do nothing. When Jake decide to react can also be what prompt their Shadow Guides to act too.
The Aether manipulation that Jake, Erwin and Lu Yan do is like Nen control in HxH. If a body part is strengthened, it means there is less Strength Aether elsewhere ect... I hope it is clear for everyone.