A Hand denoted a member of the One Sith during the time period of approximately 130 ABY. These individuals were the most skilled and effective subordinates of Darth Krayt, specifically trained and purposed to execute his commands. They were exclusively under his direction and reported solely to him.
Krayt's Hands on Vendaxa By the time of 137 ABY, Darth Nihl was Krayt's sole Hand, having received the position following the unexpected death of his predecessor during the Massacre at Ossus. In that very year, Krayt appointed Darth Talon, a Twi'lek Sith Lord, as his second Hand, a decision that caused displeasure in Nihl.
Following severe injuries sustained by both Talon and Nihl in a battle with Cade Skywalker during the grievously injured, Emperor Krayt selected Darth Stryfe as his new Hand, replacing the now demoted Lord Nihl.