Goetia #11 (just that one time though)
Languages, transportation, widows
Like many demons whose specialty is winning the love of women, which Sucax does “most marvellously,” Sucax appears as a gender-ambiguous figure (a man with a woman’s face), or a beautiful woman.
Sucax is a typical general-purpose demon, good for travel and teleportation, teaching any languages, and, predictably, gaining the love of women. Worth mentioning, he’s specifically invoked for gaining the affections of widows. Book of Oberon says that of all the many spirits that do this sort of thing, Suchay is “the most principallest.”
Mildly interestingly (or not, your call), Sucax is listed as a member of the Goetia (#11 of 11) in one grimoire only: the Munich Manual of Demonic Magic, though he gets a mention in the occasionally eccentric Book of Oberon. This might be an interesting creature to show some of Oberon’s sources.