Only the leaders sent by each family are Fourth Tier forces, and each of them is merely at the early stage of Fourth Tier.
After all, not everyone is a freak like Zi Liyuan, for whom upgrading is as easy as drinking water.
Back then, he went all out to exploit the Empire's resources, nearly crashing several public upgrade instances.
If it weren't for Wang Tie's father stopping him in time, this guy probably would have ruined all the public instances created by the Empire single-handedly.
As for the rapid upgrading of his several women, one of them relied on him, while the other benefited from Shen Yurou's research into various thermal weapons and technological products.
From low-level to high-level, exoskeleton armors, mechs, and Gundams, these things significantly increased combat power.
Later, the Empire was able to sweep across the globe, destroying the Coalition of Nations and wiping out enemy legions, all thanks to the various thermal weapons developed by Shen Yurou.
