Fake memories

In the realm of demons, technology wasn't as advanced as in those worlds that had sci-fi themes. But still, it was much more advanced where demons had invented a way to use mana as their daily life energy source instead of using gas. 

There were aircraft, airfields in the sky, floating islands but those were naturally formed. 

There were flying cars but demons prepared to ride on the ground because they would increase car accidents and invade people's privacy. 

Buildings with holographic screens floating around them, teleportation gates at every stop instead of long-distance subways. People were at their peak of using advanced technology and transportation system.