Watching the Daoist Quan actually have an arm burned off by Yang Zhen with a single strike, both Ren Changsheng and Lu Ziyue expressed shocked expressions on their faces.
The attributes of the two Companion Heavenly Fires were completely different, and they could even feel that the two types of Companion Heavenly Fires Yang Zhen possessed were almost at two extremes. Under such circumstances, the fact that Yang Zhen could fuse them together made it unsurprising that he could burn off an arm of Daoist Quan, let alone kill him with a single blow. There was no surprise there.
The reason Ren Changsheng and Ji Ziyue were so shocked was precisely because Yang Zhen had done the impossible by fusing the two types of Companion Heavenly Fire together.
Although they wanted to ask Yang Zhen how he managed it, such in-depth questioning was not something disciples from the Heavenly Moon Sacred Ground would do.