It is a little-known fact outside of the field of demonology that the demon Mercuriat occasionally adopts a human guise.
These incidents are rare, but over the course of several millennia, a number of them have been documented by credible sources, and it is likely that these documented cases are only the tip of the iceberg. Researchers analyzing these incidents for any sort of pattern invariably come away disappointed, for there is little that connects the false human identities that Mercuriat adopts. Age, race, name, appearance, and (claimed) occupation all vary wildly; the demon does seem to prefer male identities, but the significance of this tendency is yet unknown, as is whether there are any exceptions to this apparent rule.
Mercuriat is Neil, the single father; is Lee, the hard-working college student; is Stefan, the out-of-work actor; is Ahmed, the eccentric widower; is Felix, or Omar, or Rodrigo, or Daniel... the guises are many, varied, and seemingly unpredictable.
For certain demonologists, this has led to overblown paranoia about which past personages might have been Mercuriat in disguise. Some speculation is only natural, and may well uncover cases that had hitherto been overlooked or disregarded; however, this is not the same as theorizing without evidence that many historical figures were in fact demons in disguise, and that humanity must be thoroughly established for each subject of speculation before the idea can be safely disregarded. As it happens, Mercuriat's known human personae tended to be obscure figures that would draw little attention from the general public; any as-yet unknown identities are likely to follow this rule as well, and thus would not be names that dominate our history books.
What meaning this tendency of Mercuriat's has, and what benefit he gains from is, is a subject of much discussion but little agreement. Worth noting is that this is not the only instance in which Mercuriat holds an unexplained connection to humanity: see his link to the famous Pines family, for instance, or his generally humanoid appearance. As in these other cases, academic discussion generally is divided into two camps. One camp holds that, for any number of postulated reasons, Mercuriat has bonded with the human race, and that he holds a sort of affinity for humankind. The other camp holds that any affinity Mercuriat affects for humanity is merely an act, and that he connects to humanity solely to better understand his most frequent source of prey.