Morgana La Fay - Pen 1: "The Goddess of Winter" Parts 1-3, "The Stone of Destiny", "Quest's End".-- "Seeds of Change" -- Expatriot, The Sleepers, "Iris, Lily, and Rose" parts 1 and 2, "The Once and Future King" parts 1 and 2
James Seabairn - "The Once and Future King" parts 1 and 2
Zbriegniev - Morgana's henchman mentioned in "Iris, Lily, and Rose" part 1
Sybil, The Queen of Northgalis - Pen 1.01 "The Crystal Cavern" -- Pen 3.09 "Iris, Lily, and Rose" parts 1 and 2
Nigel Sefton - "Expatriot", "TOAFK" parts 1 and 2
Ms. Fadiman - "The Reluctant Thief", "My Angel Brianna"
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Montrose Company:
Darien Montrose- mentioned in Gar 1 "Prophets and Angels" but not seen on-screen in that one. His first actual appearance is Pen 1.01. "The Return". "The Watching Eye", "Quest's End" -- "Triangles", "Lethe", "In The Blood", "Night of the Weird", mentioned in "The Rising" part 1, "Signs and Portents", The Yorkshire Adventure, Lethe.
Bruce and Stephen - Darien Montrose's lackeys. - Pen 1.01 "The Return", "Visions", "The Watching Eye", "Quest's End" --
Mr. Oswald Reeve - works for Montrose's company, might be his right-hand man. "The Watching Eye"
Mabel - Darien's secretary. "The Watching Eye"
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Illuminati
William Powell - "The Watching Eye" -- "My Lady Fair", "Triangles" -- referenced in "Expatriot", in "Iris, Lily, and Rose" parts 1 and 2
Pratchet - Powell's aide. (not neccessarily Illuminati, just easier to keep him with Powell for right now.)
Jacob Feldman and Arthur Ratcliffe - "The Watching Eye" -- "My Lady Fair" -- "On Holiday" parts 1 and 2
Hector Duval/Lancelot - on the phone at the end of Pen "The Goddess of Winter" Part 3, In Flashbacks in "The Goddess of Springtime", flashbaks in "the Ill-Made Knight" parts 1-3, "Visions" -- "Triangles", "The Darkest Hour" part 1-- "Iris, Lily, and Rose" parts 1 and 2, Ripper,
Giles - (Duval's aide) "The Darkest Hour" part 1 -- "Iris, Lily, and Rose" part 1, Ripper
Enid and Faruz - "Visions".