One man army

With an excessive amount of soul force within his body, Kyle only had to annex it in order to use his wind affinity freely.

Under normal circumstances, this would require some time. 

But his entire body was swept through by adrenaline, giving a slight boost to the acceleration process.

At the same time, his focus didn't have to be fully on the annexation process.

Instead, he was able to pay attention to the Ghosts that were trying to attack him with their incorporeal bodies.

However, before they could even reach him, Kyle made use of his wind affinity. 

This accelerated the speed at which he could run, and move around.

His wind affinity also allowed him to move the silver serpent spear with a terrifying velocity. 

The impact severed the Ghosts in two halves, sending them to the afterlife.

Or at least that was what would have happened under normal circumstances if Kyle's body wouldn't have devoured their souls.