Installing Formation Arrays

After discussing other things, Yun Shang and Guo Xuehua immediately left the Xian royal palace because they had stayed in the Xian Kingdom for a few days to meet Zhang Fei.

"May I ask about the Star Tower, Emperor?"

Xian Feng nodded to Zhang Fei. "What do you want to know about it?"

"What is the main requirement to challenge it? Do I have to join a sect to be able to challenge it?"