The Crimson Hand were a group of alien criminals who commited many crimes throughout the universe. The Tenth Doctor's companion Majenta Pryce was once a member of this organisation. Among their crimes were fraud, grand larceny, and murder. They were wanted by Intersol.
The Crimson Hand was composed of people who wanted wealth. Among them were ruthless tyrants and corrupt tycoons. They held many items of power including a piece of the Key to Time and the Scroll of Horath. Their greatest prize was the Manus Maleficus, which granted the highest great power. They used it to destroy many planets, including the Skith Home planet. Majenta Pryce soon grew fearful of the group and fled.
They remained silent and unknown until they attacked Intersol, the police group that was trying to stop them, destroying Justice and its leader, Finn Dargo. They managed to take control of Majenta Pryce. However, Majenta managed to break free of their control, and used the power of the Manus to destroy them. In their final moments, the Hand vowed that somehow they would return. (DWM: The Crimson Hand)