When an hour passed and the army was yet to attack, Silva decided to give them a warning, so he cast a formation with only a snap of his finger.
The formation formed above the castle and was pure black in color. From the formation, a black flaming ball was released, and it fell straight for the castle.
But the castle was not undefended—a barrier covered the castle and attempted to block the attack. The fireball slammed into the barrier, and the barrier trembled before melting.
By the time the barrier was melted through, the fireball had died down. But Silva didn't attack again; he could have used the hole in the barrier to release a second attack, but he only did that first one as a warning.
And it seemed the warning worked, as troops began rushing madly out of the gates of the city, mages and warriors alike.