 Mortimus is seen as part of a group of students, taught by Borusa among others, known as the Deca, a group of activists campaigning for more intervention, alongside the Doctor, Ushas, Koschei, Magnus, Drax, a spy named Vansell, Millennia, Rallon and Jelpax.He aids the Deca in learning about the Celestial Toymaker, several members of which then undertake a disastrous trip to his realm.<ref>Parkin, Lance & Pearson, Lars (2012).