Diamond Queen

Twelve years ago, the master thief known as the Queen of Diamonds, head of one of the largest black-market organizations in the universe, disappeared. When she returns to the world she once knew, she discovers that her entire empire has turned into something horrifyingly unrecognizable in her absence.
The underworld organization she had so carefully created all those years ago has now been taken over by a band of vicious assassins who now rule their sector of the universe through fear.
When the assassins learn of Diamond's attempts to resume control over her organization, they determine that she must be separated from Knave-her ever-present shadow and bodyguard-and killed. As she fights to stop the destruction of everything she holds dear, assisted by the only person she knows she can trust, the Queen of Diamonds must come face to face with her own demons and a past she had long kept buried in her memories.