Ji Changsheng had already refined the Thunder Crystal that Bodhisattva Guanyin had warned him about earlier, mastering the Thunder Method, but only to a beginner's level. He didn't have time to delve deeper into his cultivation.
Ji Changsheng's Thunder Method, as of now, couldn't even kill a Nascent Soul cultivator, let alone a Mahayana level one like the Master of the Life-Prolonging Guanyin lineage. At most, it could kill a Golden Core cultivator.
The death of the Master of the Life-Prolonging Guanyin lineage was the doing of his beloved foster father.
Old Devil Yu had launched his attack just outside the hall earlier.
Then he coordinated his moves with Ji Changsheng.
Ji Changsheng was prepared for the chance that his bluff would fail. After all, the Master of the Life-Prolonging Guanyin lineage was of the Mahayana Realm and his foster father wielded a sword. It's normal that his foster father wasn't Yu Linglong who could instantaneously kill a Mahayana stage cultivator.