Exhaustion

Compared to the four magic crystal cannons which were ceaselessly roaring, Black Raven City was rather silent. Its ruler, Lord Zaganide, had always considered offense to be the best defense. Interestingly, his old rival, Dismark, was the exact opposite, and excelled at exhausting his enemy's strength with his city's defense.Thus, Black Raven City didn't possess a single magic crystal cannon, while Holy Crown City had over fifty. If one were to attack Holy Crown City with only four magic crystal cannons, they would have been reduced to ash before they could blink.

Black Raven City, however, had no such luxury. All they could do was silently weather through the barrage, powerless to retaliate.