Branded Possession by Cari Silverwood

Humans are precious on Aerthe.
The Mekkers want humans, to sell them, to keep them as toys, to drain them of blood for Factor H, a nutrient they need to survive.
Except for Gio.
Gio killed the portal maker. Now she is to be broken by Ryke, the King’s Own Lawgiver, a hooded, scarred man who kills people as if they were insects underfoot.
She will pay for her sins with her body, spill her secrets, and sob out her misery on Ryke’s f***spears.
The man has his ways and no one has ever escaped being broken.
Clinging to hope, Gio prays she can still save her people.
But is there more to Ryke than torturer extraordinaire?
Deep in the Underdeck of the royal landship he and his new toy, Gio, will wrestle with secrets from his past and maybe, just maybe, discover a way for his despicable people to salvage what’s left of themselves and find peace on Aerthe.
Inspired by the Gor series by John Norman

Warning:
This is a dark story with complete power exchange. If you don’t understand where dark books can go this may not be the story for you.