Abyssal Saintess Elcadia:
According to Solina's Biography that we read in the library, the Embryo group is deeply connected to Saintess Solina. But there is almost nothing about Solina herself. Of course, it would be her nature to let people know only what she wants them to know.
Anyway, in order for us to investigate the real identity of Embryo, we need to search the Monastery of Silence and track down her past.
Monastery of Silence?