Planet Leviathan — D.J. Goodman

The cyborg commandos of the Galactic Marines are the greatest warriors in the galaxy, but sometimes one will go bad. Too unstable to be let back into the general population and too powerful for a normal prison to hold them, there is only one place they can be sent: Planet Leviathan. Stacia X-79 has been tried and convicted of trying to kill her commanding officer. Now, trapped on the planet that nobody can leave, she's on a mission of revenge. Nothing can get in her way, not the bizarre monsters roaming the surface, not the insane military commander who has set herself up as the local warlord, and not the seismic forces of the planet itself. She will find the son of the person who sent her here, and she will kill him. Even if it means giving up her own life.