Mengxi and Yumo illustrate have been posted in chapter 00 (Charectar)
The position of the Holy Maiden or Holy Son is second only to the Pope within the Asumos Church. They are the second in command, wielding great power. Even the three Archbishops treat them with utmost respect, and in matters of divine revelation, the authority of the Holy Maiden surpasses that of the Pope.
However, ever since the previous Holy Maiden (Saintess) was killed by a Demon king called "Higanbana" over two hundred years ago, the position of the Saintess has remained vacant. During this time, the people of the Asumos Church have been trying to find a new Saintess or Saint.
(Higanbana è (red spider lily) in Japanese)