Below the inner base of Black Fortress, various explosions could be heard once in a while. *BOOOMM* If it is not because of a powerful enchantment in the underground wall, the whole Black Fortress may already shake many times.
In the Black Fortress, the strongest place and the most secure place is not the wall or inner base, but their underground room and its foundation. The underground room is heavily reinforced by many materials and runes.
It is said that once, few grandmaster enchanters even lay a powerful rune on it. It even rumored that this enchantment could hold the attack of a Monster Overlord or seventh-grade combatant a few times.
The enchantment is not only to defend the Black Fortress foundation, but it is also to prevent any monster breakthrough from the underground and pass them easily.
