Magnus, also known as the War Chief, Koschei, the Master, Missy, and various other aliases, was a renegade Time Lord. He/she was considered by the Doctor to be his nemesis. Magnus was responsible for several of the Doctor's regenerations.


  • First - This incarnation used the title of Magistrate.
  • Tenth - This incarnation went by the title of War Chief.
  • Eleventh - This incarnation used the name Felix Kriegslieter.
  • Twelfth - This incarnation went by the name Koschei.
  • Thirteenth -This incarnation went through several stolen bodies in an attempt to circumvent the regeneration limit.
  • Fourteenth - The first incarnation of the regeneration cycle granted by the Tzun. It didn't last.
  • Fifteenth - Freed from the Eye of Harmony, this incarnation impersonated the Doctor.
  • Sixteenth - Resurrected by the Time Lords, this incarnation resembled a child.
  • Seventeenth - This incarnation disguised himself as Professor Yana, his disguise so convincing even he forgot his true identity.
  • Eighteenth - This incarnation took the alias of Harold Saxon.
  • Nineteenth - The Master's first female incarnation. She went by Missy.