William created another group of masters, who were tasked to take care of any escaping outer world masters. This group had to act fast, or else the escaping masters would create more troubles than expected.
It just needed a few waves of masters to get delayed for other outer masters to escape the formations. So, he made sure to pick a few of the strongest masters in the firefighting group.
A third group would deal with the entrapped outer world masters. This group had to be brutal, using deadly attacks and techniques. To make sure things would be quite good, William started to make different augmenting formations of his, the same type Fang was obsessed with.
These formations depended entirely on materials from the outer world. But this wasn't a problem anymore. After days of gathering these materials from the underground city, William had more than enough.