The Deca was a group of ten young Gallifreyans at the Prydon Academy, which included the Doctor.
Overview
The group represented the top rank of students in their class (MA: Divided Loyalties), despite the fact that the Doctor seemed to have excelled academically. (DW: The Ribos Operation)
- The Time Lady Ruath implied to the Doctor that the students in The Doctor's social group (which she did not name), all had Borusa for a teacher. (MA: Goth Opera)
To the group, Ushas (later known as the Rani), Vansell and Rallon had nearly completed their courses. Rallon was, however, at some point, taken over by the Celestial Toymaker.
Of the others, Millenia was forcibly made part of the Celestial Toyroom. The Master (then named Koschei), the Monk (then known as Mortimus, the Rani, the War Chief (originally Magnus) and Drax, and, of course, the Doctor, eventually took up lives as renegade Time Lords.
Jelpax and Vansell would go on to hold down conventional roles in Time Lord society. (PDA: Divided Loyalties)
- The former would be Cooordinator of the APC Net and the latter would go on to head the Celestial Intervention Agency.