"Reills. E'en the name makes me shudder. That there is unholy ground, cursed by most gods. Not even the demons and devils and the incarnations o' evil dare step foot there. Reills. You know me, I think money likes it in my pocket instead of wherever else it is. But, and I've heard rumors that say this, if theirs treasure on that ground, it ain't going in my pocket on pain o' death."
-Old Gerald, man in the pub.
Whilst exploring underground the PCs discover tube like tunnels stretching for miles, upon further inspection the strange tunnels seem to connect all major cities in the are, what is their purpose?