The Fake Great Patriarch Sword Saint

The battle was actually not over yet, at least for Ji Yuan.

After Ji Yuan had killed the Immortal Abyssal Gong Nephilim, he quickly displayed his Million Swords Field with his life and death sword domain, creating volleys of profound swords against the citadel walls that housed the mighty cannons.

Although the citadel walls were made of black celestiums and were extremely sturdy, but against the life force energies swords of Ji Yuan's Million Swords Field, the cannons totaled six in all were all completely destroyed.

Two of the huge cannons had been used against Ji Yuan and it had a slow recharge speed. 

Luckily for Ji Yuan and the Ancient Old Ones, these 6 huge cannons all had the same power source and only 2 could be fired at any given time, with the other 4 acting as reserve in case a cannon was destroyed.

And Ji Yuan had already taken the blunt of profound energies of the 2 cannons.