The Deca was a group of ten young and rebellious Gallifreyans at the Prydonian Academy, which included the First Doctor. (AUDIO: The Rani Elite)
The Fifth Doctor had a dream about the Deca in which he was still in his first incarnation and back on Gallifrey. (PROSE: Divided Loyalties)
The group represented the top rank of students in their class, (PROSE: Divided Loyalties) despite the fact that the Doctor was said to have not excelled academically. (TV: The Ribos Operation)
- The Time Lord Ruath implied to the Fifth Doctor that the students in the Doctor's social group (which she did not name) all had Borusa for a teacher. (PROSE: Goth Opera)
Of 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.
Millennia was forcibly made part of the Celestial Toyroom. The Master (then named Koschei), the Monk (then known as Mortimus), the Rani (formerly known as Ushas), the War Chief (originally Magnus), Drax, and the First Doctor eventually took up lives as renegade Time Lords.
Jelpax and Vansell went on to hold down conventional roles in Time Lord society. (PROSE: Divided Loyalties)
- The former became Coordinator of the APC Net and the latter went on to head the Celestial Intervention Agency.