It was a basic profile of Shyloris and the twin presence residing within her.
By origin, Shyloris is a time-locked character, having partook of the immortalizing nectar of the Amaranthinae Lily. Over the years, she meets Neiro prior to his encounter with Silas, and the Numen becomes her anchor.
Despite the nigh omnipresent abilities of the Numen, however, there were times when Neiro would be away.
It was during one such period that Shyloris happened upon an engraved silver pocket mirror. Upon polishing and gazing into its reflective surface, came an unguarded moment, and in that instant, befell the curse set upon it and the being within. The shade within the mirror had likewise bound her and they now coexist, both souls tied to the mirror and one another.
By gazing into the surface they can swap in an out. While the one in the mirror can travel across all panes of the "Aether" and are safe from most harms of the material world, their life is protected only by the physical safety of the mirror itself, likewise does current inhabitant of the physical form hold the other's life in their hands.
As such Shyloris has had to overcome much working with her shade, who is as much bound to her as the reverse. Oddly enough the immortal isn't as upset about the situation as most in her position would be to hear themselves bound, and is in fact rather spirited about. Something that her gloom could not at first comprehend.
The two learn to coexist, protecting one another from harm. Where one falls short, the other picks up and as such they work over their shortcomings.
Neiro and the shade seem to be acquaintances, and the Numen seems to sympathize with the plight of both Shyloris for her perpetual existence, and the Shade's fixation.