C515 yin and yang Warlock

Yin? Yang? What did the two words mean? Why was it carved into this small jade slip?

When Shuo Yue saw the two words carved on it, her expression changed greatly.

He lowered his voice and said, "OP ?" "I seem to already know what kind of organization this is ?"

"Ah?" You already know about it from the short term? It seems like this organization has existed for quite some time