Arthur Langtry is one of the oldest and is most likely the single most powerful wizard on the White Council.
Langtry is tall and broad-shouldered, and has cold blue eyes; he wears his hair long, and has a long silver beard.
His hair and beard is long, all snowy white with threads of silver, and perfectly groomed. His eyes are winter sky blue and alert, his features long, solemn, and noble.
In Turn Coat, he talks mind-to-mind to the essembly at large, directing hundreds present what to do and not do during the Mistfiend attack. And, he tells Harry Dresden to capture Peabody who is escaping. 
Magical Gear and Garb Edit
In Changes, when he and Harry meet in the warden's Worry Room the Merlin of the White Council was dressed in simple white robes. He also wore a gunslinger's type belt of white leather hung at his hips. It looked something like the tactical gear made for Special Forces operators. Multiple potions vials rides in individual leather cases and the leather-wrapped handle of an anemic rod or a stubby wand pokes out of his holster. Several of the pouches were fastened closed, and looked as though they would contain bits and pieces of the standard wizard gear. He also bore a long, white staff, a simple wooden pole made of an unfamiliar wood.
In the SeriesEdit
In Turn Coat, while Listening, Harry learns that Arthur is the one pushing Listens-to-Wind to perform the ritual to find the real killer. Peabody takes Listens-to-Wind away for signatures. Harry approaches him, offers help in exchange for copies of Morgan's file. Arthur's condition is to find the traitor, the real killer, not simply prove Morgan's innocence.
At the end of Turn Coat, LaFortier's supporters claim Merlin ignored their safety and was negligent with security. Arthur decided to allow rumors saying that Morgan and Peabody conspired feeling that it was better to appear as having acted with deadly strength and power. This also allows those behind Peabody to know that the Council killed an innocent man and one of their largest military assets. The Merlin had asked Klaus Schneider to decline the Senior Council seat. The seat went to Gregori Cristos who threatened that he and all of his allies would secede if he didn't get the seat.
In Changes, Harry sees the Merlin in the Warden's Worry Room. Arthur doesn't buy into Gregori Cristos's currying up to Arianna Ortega for peace with the Red Court. But a lot of wizards on the Council do. So, he's putting up a pretense with his own plot in the works and demands that Harry play along, that one child is not important compared to hundreds of children. Harry does not agree and leaves.
- Senior Council
- White Council
- The Original Merlin
- The War
- List of Battles in The War
- Ebenezar McCoy
- Martha Liberty
- Gregori Cristos
- Ancient Mai
- Aleron LaFortier
- Simon Pietrovich
- Seven Laws of Magic
- Black Council
- Grey Council