The man at the front has the cultivation of the God Transformation Realm. His face is covered with a black cloth, and his aloof eyes are unbelievably calm. He is most likely a trained martyr.
It is easy to find an Innate Realm martyr, but a God Transformation Realm one is much harder. The resources required to train such a martyr could be better used to train a more flexible disciple.
For a large and impressive sect like the Imperial Sect, an Innate Realm martyr is the limit. Unless there is a special need, they would never waste resources in this way.
Therefore, when Lu Bei saw this martyr, he felt honored and began to doubt Fox San's previous statement.
The attack wasn't really an assassination, more like a lesson.
Is it possible that it was indeed an assassination, and the delay in intel from West King Mansion led them to misjudge the true power of him and his brother?