Raldeth was a commander in the Chancellery Guard of Gallifrey.
During the Dalek invasion of Gallifrey, he was the leader of the Guards working to repel the Dalek forces. (BFA: The Apocalypse Element)
In an alternate timeline, he met CoordinatorVansell when he returned to Gallifrey and took him to see the Lord President. (BFA: The Sirens of Time)
Notes
The character's name has alternately been spelled and pronounced both "Raldeth" and "Reldath."