Fomor servitor

Fomor Servitors, nicknamed "Turtlenecks", and commonly called "Servitors", are altered humans that serve the Fomor. They first appear in Aftermath and again in Ghost Story.

Description
Fomor Servitors are humans the Fomor have altered by instating such things as: gills, extra muscles, organs for sonar, night-wision eyes and other things. They function as the Fomor guard dogs and thugs. They also often are the Fomor interface with humans, as the Fomor are easily irritated. Like in the case of Nothing taking over the conversation when Murphy was bargaining with the Fomor Lord in "Aftermath".

Servitors are rough-looking men, dressed only in black, all of them wearing black, turtleneck sweaters and carrying guns, clubs, blades, machetes and axes. They show some sort of sonar capability they can use to locate prey.

Many of them, such as Nothing and Listen, are extremely intelligent and capable.

They take people right out of their beds, they steal children waiting for the school bus. They've tortured people to death just for the fun of it.

They are likely made to serve by the Fomor with some very powerful mind magic, as they no longer seem to have any desire for anything other then the will of their masters. They are happy to kill, take severe unwarranted punishment, or even die at the whim of a Fomor Lord. Thus far all of the many Servitors have all been male.

Both Harry Dresden and Karrin Murphy call them Turtlenecks because they all wear black turtleneck sweaters, likely to hide their gills.

The odd parts grafted on them turn to ectoplasm when they die and the police call them "transients".

In Aftermath, Murphy interacted with one called Nothing, who had he had gills under his turtleneck sweater. Another one mentioned is Listen.

They're shown using sea urchin-like projectiles that spew acid. and a number of more mundane weapons such as guns, clubs, blades, axes, and machetes.

"Aftermath"
In Aftermath, Karrin Murphy encounters them trying to rescue Georgia, William Borden's pregnant wife, from the Fomor.

Ghost Story
In Ghost Story, Lea sent Servitors to attempt capturing Molly Carpenter for their Fomor masters in order to test her new fighting skills. Molly told Harry all about them. She told Harry how one of them had captured a little girl and had her trapped in a gym bag while he paid a cop to look the other way—Molly made an illusion to make the bag of gold look like a gun. The cop shot the Servitor and the Servitor broke the cop's neck before he died.

The leader of the group of Servitors, Listen, that attacked Molly relayed a message to the Grey Ghost from his leader.

"Bombshells"
A Fomor Lord ambassador who came with a group of Servitors led by Listen, was assigned by the Fomor Empress to sign a non agression treaty with the Svartalf. However, the Fomor Lord wanted revenge on Marcone, who was a guest at the proceeding, for the events in Even Hand. To do this the Fomor designed a bomb to kill Marcone, along with all of the other Svartalves guests, and about ten thousand other innocent people in the area. The Fomor and the Servitors were stopped by Molly Carpenter with the help of Andi, Waldo and Justine. The betrayal of guest right also stopped the treaty from being signed, to the good of humanity.