- You may be looking for Castellan of the Chancellery Guard.
The Chapter Castellans were Time Lords tasked with ensuring the security of Gallifrey with their respective guards. They belonged to the Castellans' Office.
Wynter was appointed Chapter Castellan of the Arcalian Chapter by President Romana not long after he had left the Time Lord Academy. Narvin attempted to get his support by telling him that Romana might some day abolish the castellans. (AUDIO: Lies)