Doyle

Doyle was the Captain of the Queen's Ravens, her assassin,  and the acknowledged champion of the Unseelie Court. It was said that when he spoke the Queen's words come out. His livery is a spider. He is often referred to by Andais as "My Darkness" or in general, "The Queen's Darkness."

Doyle had once had a wife and child but both of them died.

Doyle had been the Queen's Darkness for over a thousand years, and though he loved her once, his loyalties have shifted to Meredith.

Doyle does not like modern modes of transportation such as airplanes or cars; there is too much metal in either mode of transport for him to ever feel truly comfortable.

In A Lick of Frost, it is revealed that he is one of the fathers of Merry's children and therefore will be a king to her queen.

Powers
Bearer of the Painful Flame - he can create from his hands a sickly greenish flame able to bring the true death to immortals.

Bespell - He is able to bespell others with the flickering lights in his eyes.

Doyle is capable of traveling through mirrors as well as communicating through them.

Healing - He can heal a minor wound by licking the wound as a hound might, the Queen labeled him "Baron Sweet-tongue" for the ability. He once had more powerful healing abilities but those powers were lost.

Shapeshifting - He was able to shape shift into a Gabriel Ratchet (hell hound or hound of the hunt) and a horse, but he had lost this ability. He regained this ability and can now change into an eagle as well.

Can wrap himself in shadows and become unseen.

He is able to remove a spell, add some of his own magic to it so that it returns to the person who created it and then follow it as it goes.

Weapons & Artifacts
Bainidhe Dub a.k.a. Black Madness - A sword that brings madness upon any who might try to wield it other than Doyle.

Snick and Snack - Twin black daggers forged together at the time of their making. The daggers are able to hit any target once thrown. Their true names have been forgotten.

Horn of the Dark Moon a.k.a. the Horn of the Hunter or the Horn of Madness - A black, curved instrument formed from from the horn of some animal with a strap so it can be worn across the body. It can only be touched by the huntsman and only when the magic of the hunt was upon them

A Kiss of Shadows
Doyle was sent by the Queen to Los Angeles to bring Meredith home. He saved Meredith from Alistair Norton by sending spiders through the wards around the house and warned Meredith to hide before he ultimately shattered the mirrors. He revealed later that he watched the ritual between Merry and Roane. His observation to Merry was that two sections of the bed's headboard were melted, indicating that Merry would later manifest two hands of power.

Doyle served as her protector again when Merry was being pursued by the sluagh and came through the mirror into the bathroom to rescue her. Once with her, Doyle revealed he was sent by the Queen and gave Merry the Queen's mark of protection through a kiss.

Doyle served as one of the two required sidhe witnesses to Merry's hand of power manifesting and supplied the Queen's own blade, Mortal Dread to kill Nerys the Grey.

Doyle later revealed the meaning behind the nickname, Baron Sweet-Tongue when he healed Merry's wounds at her apartment. He then escorted her back to the Unseelie court, and while there, served as a constant support as she confronted her cousin Cel, awakened the roses, and set up alliances with the goblins.

It was in this book that Doyle's loyalty to the Queen began to waver toward Merry.

Doyle returned with several other guards to Los Angeles with Merry.

A Caress of Twilight
Meredith realized that Doyle had maintained control of the guard and was disappointed with her for not using the alliances she fought hard to gain.

Doyle also realized that his attempts to remain mysterious by absenting himself from Merry's bed  backfired. Merry had only  grown closer to her other lovers, allowing her Darkness to become remoter.

Andais revealed to Merry that the true reason she never took Doyle into her bed was for fear he would be king in truth, not merely in name.

Along with the other guards, Doyle helped Merry defeat the Nameless.