Quite intriguing for the most part.
I'm guessing the darkness can't do much beyond its domain besides latching on to one's mind. It'd be too weak to do anything beyond its source. One would have to had entered its influence to be affected by it. Without a clear source and domain, it'd dissolve before it could do anything. I doubt Chase would cause hysteria in Adastra. Unless Adastra itself already harbors darkness rooted within its lands.
Though it'd be interesting to see Chase fight off the darkness, he'd need literal magic to do so. Preferably one that can enforce the natural laws, something that can suppress chaos manifest. Highly doubt Chase could produce such weaponry, let alone the technology for it.
Such a story could be great with a few tweaks here and there.