Technologically advanced? Nope. But they're far more advanced where understanding magic is concerned. And that's looking at it as a whole. Lower classed "demons" aren't even very smart, although the more advanced ones are. They also have far greater numbers than humanity, but their advance is limited by the red mist they must have to live. Only at certain times times - and at certain special locations (the mines for "God's punishment stones") - can they erect a tower to spread the mist. That time is a few years away. They do have a portable storage tank they can wear to operate outside the mist for a limited time.
And they aren't the only rival race either - though we won't see the other for a very long time. The enemy of my enemy is... still humanity's enemy. You might compare them to Zerg. And it is the "demons" who currently hold them back. Furthermore it is their spores (or something) which turn regular animals into "demonic beasts" so they're definitely affecting humanity despite no direct contact.