Who is Phanes?
In Genshin lore, Phanes is the mysterious primordial god who emerged from the egg of the universe, brought order, and created Teyvat. Phanes is heavily associated with light, creation, and divine authority.

Who or what are the "Shades"?
The term "shades" appears in reference to seven entities created or associated with Phanes. The term is vague, but from context and lore fragments, here's what we know or can infer:

Shades = Divine Extensions: They may represent aspects, reflections, or avatars of Phanes—almost like divine fragments or servants.

Shades as Loyal Servants: The word "shade" can mean shadow, copy, or spirit. In many mythologies, shades serve their creator or master, sometimes in an almost worshipful or submissive role.

Shades as Concubines?
In symbolic or mythological terms, yes—shades are like concubines:

They are created by or bound to Phanes.

They serve him, likely without equal agency.

Their existence is tied to his will, much like concubines serve a king or emperor for legacy, pleasure, or symbolism.

The power dynamic is unequal—Phanes is the origin, the absolute, while the shades are extensions or lesser beings.

In mythic or divine cosmology (similar to Gnosticism or Chinese creation myths), creators often split themselves into subordinate gods or spirits that are both children and servants—sometimes even treated as vessels for the creator's continued influence or glory.

So while not sexual, the concubine comparison fits in the sense of:

-Devotion
-Creation from one source
-Serving a higher authority
-Being part of a divine "harem" of subordinate powers

Summary
Yes, in symbolic mythological terms, the shades can be seen as Phanes' concubines, not in a romantic or sexual way, but as servants, fragments, or vessels of his divine will. They exist to serve, reflect, and perpetuate Phanes' influence across the world.