The Sovereign Guard was a Kriosian organization, whose responsibilities included the protection of the First Monarch of the Sovereign Dynasty of Krios Prime.
After the September 2152 kidnapping of Kriosian First Monarch Kaitaama by a group of Retellians, she expected that the kidnappers would contact the sovereign guard, which would then pay her ransom.
Kaitaama also suggested that if Trip Tucker were to make a pass at her, the guard would respond by cutting off his hand. (ENT: "Precious Cargo")