Although that perhaps wasn't one hundred percent true, since the shadowy figure didn't force Donan to use Dark Aura, the possibility was still high. Still, even if the shadowy figure lied, his methods didn't change. He used many sentient beings and played with their lives... For all intentions and purposes, he caused a lot of problem for Leon, and that was enough to make Leon wants to kill the bastard.
"What about the technology you obtained from him?" Leon asked.