Series 3 introduced a batch of new characters and reintroduced other characters from previous series.
Treguard - The Dungeon Master
Treguard: "I am Treguard the dungeon master, referee of the game of luck and glory."
Treguard's appearance and actions changed a bit from this series onwards. Certainly a more relaxed Dungeon Master, who continued to give hints to the teams, but had less interaction with other characters.
Velda - The Elf
Strong-willed elf. She cannot be bribed but a clue object can be used as proof of integrity. One team threw down a gauntlet and another offered a rose to please her. Sometimes she can tell if the dungeoneer is harmless by their situation, often having to rescue them from goblins or the Bohemoth.
McGrew
Appeared a few times in level 2 as a guard. Helped a dungeoneer through the caves of level 2 by fighting off a magic 'claymore' sword, and had an interesting clash with Mogdred.
Mellisandre - The Maid
The maid replacing Gretel from series 2. Like her predecessor, Mellisandre was always helpful, giving clues and information for little in return, although she had an uncanny nack for standing on trapdoors. Her full name is Mellisandre Makepeace Mohapenstance (Hopefully her surname is spelt correctly; she is, after all, scarsely an inconsequential person).
Olaf - The Viking
The 'lootings and pillagings' Viking buffoon from series 2.
Hordriss the Confuser
This series is the first appearance for Hordriss. Hordriss lay neither on the side of truth nor the dark side. Strong on magic, and courtesy. Hordriss remained in Knightmare until the end.
Motley - The Jester
The replacement for Folly, and also remained in Knightmare until the end (although absent from series 7). A friend of Mellisandre, and always keen to offer help for little in return.
Motley: "This is level 1 and the fun has just begun!"
Treguard: "MOTLEY!"
Mogdred
As in series 2, he appeared in the lower levels to scare the innocent players and watchers. The dark side of Merlin's nature and his magic.
Mogdred: "Do you so pledge?"
Morghanna
A dark presence on Level 3. Ruthless and deadly: she killed in every appearance.
Merlin
As series 2, except this time he appeared in every team's quest in level 2 in his own new throne. To reach him, dungeoneers would need to perform a series of actions to reveal platform blocks and cross the pit. These actions were called 'steps' and were earned throughout the quests.
Asks 2 riddles in return for magic. Teams had to get both of his riddles correct for help.
Merlin: "That's right! Two out of two, or it just won't do."
The Grimwolds
Mrs Grimwold usually guarded the level 1 wellway room. She offer requires a bribe for help or passage, such as a bone for her dog 'Festus' (left). Her husband, Mr. Grimwold (the Ogre) often chased after dungeoneers.
The Oracle of Confusion
The talking spirit that appeared in the level 2 clue room. Dungeoneers had to lift the Helmet of Justice slightly above their heads to hear the voice.
The Behemoth
This was a non-speaking character that served no particular purpose in the series except to hurry teams along in their quest. He also served as a wellway guard in Quest 11.
Thanks to Daniel Pridham for some of the character descriptions on this page.