Warlock
A fairy with strong magic skills who is highly trained in the magical arts. In the past warlocks have been used to stop time and wipe minds. In modern times, since Foaly "had them do their thing into lithium batteries," Warlocks are still trained in the magical arts, but their training leans more towards the medical sides, such as emergency medicine. Most warlocks have a strong pacifist creed.
Demon Warlock
A demon who possesses magic that deviates itself from normal fairy magic, in the way that it may be used for time travel, and is considerably more powerful.
Read more about this topic: List Of Concepts In Artemis Fowl, Fairy Concepts