The gates of Moon Shadow City are forged from a magic metal called Golden Scale Celestial Iron, incredibly heavy and nigh impossible to open or close by human power.
The gates are protected by special magic set by Beastman Priests; only those with a special key can control their opening and closing.
Once the gates are closed, unless someone inside the city uses the key to open them, they are nearly impregnable.
At least, Ackman believes this, and it's one reason why he is confident in holding the defense until reinforcements arrive.
Ackman knows that even using a magic-guided cannon to bombard the gates would take several days to knock them down.
And he has not yet seen the enemy use such means.
Ackman assumes the enemy likely does not possess things like magic-guided cannons, otherwise, they would have already used them; otherwise, so many people would not have died.
