Amicus Arcane is a character affiliated with the Haunted Mansion.
Amicus Arcane is identified as being the ghostly librarian of the Haunted Mansion who holds a love for horror. As he mentions Abraham Lincoln having complimented his spats, it is likely that Amicus was alive at some point during the 1860s. There is also a crypt found in the graveyard of the mansion (in the books known as the Eternal Grace Cemetery and set in New Orleans) with the name ARCANE on it and a secret passageway connecting to the Haunted Mansion.
In the meta-story of the Tales from the Haunted Mansion books, (the real) author John Esposito states that he encountered Amicus Arcane on a midnight walk through New Orleans Square. Arcane gave Esposito the Tales from the Haunted Mansion stories to publish, and Arcane was subsequently credited as their author.
Amicus was created for the the Tales from the Haunted Mansion book series, being their fictional author/transcriptionist and often a character within the stories themselves. Within the books it is clear that he was created to serve as the books' analogue to the Ghost Host from the ride as in-addition to serving a similar niche, he is described as resembling his portrait, quotes the Ghost Host frequently, and has a similar personality to the character. Within the story/mythology of the attraction itself it is unknown if Amicus exists and unlikely he is the same as the Ghost Host.
Amicus Arcane is the fictional author/transcriptionist of these books and often appears as a narrator character within them.
While not directly appearing in this comic-book series, an illustration of Amicus appears within a library book on the cover for Disney Kingdoms: The Haunted Mansion issue #4.
Amicus Arcane was featured in, "Host a Ghost" merchandise sold at Memento Mori for the Haunted Mansion's 50th anniversary. He was portrayed considerably differently in this merchandise, being portrayed as an older balding man with a nervous appearance rather than having the, "Hatchet Man" appearance from the books (likely to distinguish him from the Ghost Host).
“Our mansion librarian is quite the book lover/He read every one, cover to cover/Catalogued every title in our collection/Tends to them all with care and affection/Every first edition his own memento mori/He’ll even help you finish your personal own ghost story”
- Amicus Arcane seems to be roughly inspired from the Cryptkeeper from the 1972 film, Tales from the Crypt. The film was produced by Amicus Productions (likely the inspiration for his name) and has a similar structure and plot to the first Tales from the Haunted Mansion book that Amicus is introduced in.
- The name Amicus Arcane roughly translates to English as "Friend of the Occult".
- The book Magic from the Haunted Mansion in Disneyland was also written by a fictional author meant to be an inhabitant of the Haunted Mansion, here being Phineas J. Pock.