When Logos and Pathos first brought up the fact that Rianna and Serena had relatively similar auras, it was when Zhen Liu first made contact with the latter.
At the time, Zhen Liu simply marked that as a sign that Rianna was originally from the Sacred Flame Theocracy and had magically ended up in Spider Hell via unknown means.
It wasn't the weirdest case of translocation, given his own circumstances, but it did make Zhen Liu wonder if Rianna was simply a victim of war.
However, once Zhen Liu had invited Serena to the library and properly introduced himself as the Kaijin Lord of the modern era, Logos and Pathos began to notice even greater parallels.
When two people radiate similar auras of energy, it could be attributed to them either having grown up in similar environments, cultivating the same formula, or due to being related to each other on a more personal level.
