Thunderous Arrival

Guardian's Keep was led by Zi Jing and built as a support to the Southern Tower. The latter did most of the battle and mining while the former focused on crafting and processing. With that said, those that resided in this base were craftsmen and researchers, not soldiers. There were certainly defenses and what not but the number of people that could fight in combat was pitiful compared to the other armies. 

Still, among the strongholds, Guardian's Keep had the greatest defense. 

What was the need for soldiers when there were walls fortified with layers of Deepwater Steel, towers with cannons and artillery, all manner of tricks and innovation. 

All of these things born from the minds of Zi Jing and his men.