WE ARE ALL OF US FOOLS. Mercy's hair isn't pink or strawberry blonde or rose gold or ginger or auburn or any of the options we usually consider.
You noticed the colours first, beneath that harsh and unlovely light: that the hair was a dead flower or apricot colour, and that the skin and lips and brows were of a similar hue, so that beneath the nacreous cowl the saint looked like a painting with a very limited palette; and the eyes …
But the Emperor wrapped his arms around his Lyctor as though she were a precious and runaway child; he pressed her to him, drawing down the hood and tousling that overripe rose-tinted hair, heedless of the curtseying, bowing Cohort officers in the wake of his passage.
Your eldest sister, looking distinctly green around the gills and checking long strands of her overripe-rose hair for globs, had also risen—but the Emperor said, “You. Stay,” and she froze.
Her prismatically white Canaanite robe was wrapped very tightly around her, as though she were cold, and she had bound back her peach-coloured hair as though it were a wimple.
Mercy had it worst: the knot of hair at her neck had come down, and now was springing loose in pale, rose-gold strands, and she was actually sniggering.
The Lyctor at his left was combing out her hair—it tumbled in a heavy mass around her shoulders, that curious heart-of-a-yellow-rose colour, that pinkish, reddish, goldenish shade that was not entirely appealing.
She stood there with her shoulders heaving and her hand pressed over her face, pinky-reddish hair coming out of her braid, looking unhurt but pretty sorry for herself.
And she cocked her flower-coloured head to the side so that her sweaty hair fell over her face, in that sizzling, gulping heat, and she stared at us,
At one point, she threw her head back as though she were going to yell aloud, and that weird-hued hair shivered over her back.
The collapsed body on the floor, Mercymorn’s hair tumbling close to his feet in rosy, bloodied tangles.
It's not any of these colors.
A lot of us already accept that she's using flesh magic to make it an unnatural colour. I propose one step further: It's literally changing slightly every scene, sometimes even mid-scene. Sometimes it's multiple colours at once, in ombres or streaks. Occasionally it's a colour unknown to mortal eyes that only Lyctors can see, the one Gideon describes as just "weird".
