The Alhoon of Gothic Earth

The Alhoon of Gothic Earth (real name unknown) is a lich mind flayer who crash landed on Gothic Earth when its spelljamming ship gave out. It quickly discovered it was far away from the Elder Brain and proceeded to murder its kindred still in stasis. Although it was an ordinary illithid at the time of the crash, it began to learn forbidden arcane lore and eventually transformed itself in an alhoon.

The alhoon has mastered biomancy enough to create an illithid leech that will transform a human into an illithid like aberrations and part of a hive mind, presumably controlled by the alhoon. These illithid drones appear perfectly human, but have much of the psychic powers and the tentacles of a mind flayer (but hidden inside the human skull.)

In 1893, Abraham Van Helsing encountered several of the Alhoon's drones and was ultimately captured. He was held in the lich's lair for a time before escaping. He learned from a stolen book much of its history and goals- including that it plans on inducting every intellectual person into his hive mind.