Absolute Firepower

As for the invaders, they could be easily arranged. Agricultural University had a lot of monster domestication and artificial breeding projects. Unfortunately, not all monsters could be successfully tamed and become pets or cattle, especially creatures with low intelligence, like pests. No matter how they tried to modify them, it was just too easy for them to regain their wild nature. 

Through his connections with Gu Jianbo and Ning Shewo, Meng Chao managed to get a bunch of monsters that could not be domesticated. 

Then, he got a few Nightmarish Beasts from the monster research center. They had gone through unknown mutations during the modification process and could not be controlled by humans. They were brought in as the "boss" monsters. 

This "monster invasion" was definitely stronger than the most intense invasion Blessed Heavenly Garden had ever faced.