Rookies Four

Rookies Four are a title given to the current four young Devils of Sairaorg Bael, Rias Gremory, Sona Sitri, and Seekvaira Agares.

Summary
First mentioned in Volume 14 by Mephisto Pheles and explained by Ravel, the Rookies Four refers to the four of Sairaorg, Rias, Sona and Seekvaira as "a generation gathered with promising rookies that are on an exceptional level". Azazel mentions that the reason to the exceptional abilities displayed by the Rookies Four and their servants are due to them doing something other Pure-Blooded Devils would not do: Training. Majority of the Pure-Blooded Devils would not train and only depend solely on their Demonic powers inherited to them and will simply trade off their servants whom they deem weak, but for the Rookies Four, they would train their servant instead of doing a trade with other Devils. Ravel further mentioned that even throughout the history of the Underworld, the generation of the Rookies Four and their servants belonged to those which are out of the ordinary for a rookie who still hasn’t matured.

Trivia

 * Three of the Rookies Four has had major roles in the story.