Eihort (God of the Labyrinth) first appeared "in person" in Ramsey Campbell's short story "Before the Storm" (1980). However, the being was first mentioned in Campbell's "The Franklyn Paragraphs" (1973).
Eihort lives in a network of tunnels deep beneath the Severn Valley in England. It appears as a "bloated blanched oval supported on myriad fleshless legs" with eyes continuously forming in its gelatinous body. When it captures a mortal, it offers the captive a bargain. If the captive refuses, Eihort smashes the victim to death. If the captive accepts the bargain, the horror implants its immature brood inside the victim's body. The brood will eventually mature and kill the host. According to the Revelations of Glaaki, after the fall of humanity Eihort's brood will be born into light. (Harms, "Eihort", Encyclopedia Cthulhiana, p. 96).
"Ei" and "Hort" are nouns of the modern German language, "Ei" meaning "egg" and "Hort" meaning "hoard".