@Salfaro @Tanarwater
It's for the reason
@daxrocket said, "because they didn't hear it." In the novel, Aries just grabbed Virgo, made a hole in the wall and took off, leaving rest of the people behind. It's not until Virgo stopped Aries and talked him into helping them out (so the conversation happened away from the hero's group) that the two of them went back, giving the rest of the people time to run away and meet with Ruphas's group.
Also,
@WhimsiCat Yeah, even if they knew and figured out "Aries was from 12 Heavenly Stars", as
@natchu96 said, the world knows the [Maiden] as Parthenos. So unless Sei notices it, the rest wouldn't even know that Virgo is the newly assigned Maiden.