To be fair, amongst those from Luoism who received the Invitation from the King of Hell, only a small portion of them died. Those who got killed were either extremely evil or were cultivating some form of cruel and evil techniques, both serving as good reasons for Shen Lian to kill them.
After Shen Lian's intervention, there were only two of them left who were capable of competing in the Daluo Devotion Ceremony.
One of them was Zhao Xiaoyu's Nine Lotus Order, and the other was Sacred Nun Qingyin who had the support of Guangqing.
In terms of mana, even if Sacred Nun Qingyin had three times her power, it would not stand a chance against Zhao Xiaoyu. Even if injured by the assassin from Tianwaitian, Zhao Xiaoyu would still be able to triumph over Sacred Nun Qingyin.