According to a reliable source of mine......

During the time the Crystal lost its function, we've confirmed that an uninvited guest managed to slip into our city.

And that fellow is actually......

A demon...

Demon?

And what's even worse...

This guy's got his hands on something extremely dangerous.

A Demon King Bomb!

Made from materials derived from the scales of the Demon King's corpse...

The demons then hand these materials over to be used inside of a gnome-crafted explosive.

As you know, there's a few gnomes out there, who'll do absolutely anything for money.