The Dead Never Die

I am teetering on the edge between “this is cool” and “this is blatantly stealing other characters to sound cool.”

First we had the casual mention of other series, Dresden, Iron Druid, a couple others I'm not familiar with. Then we had an actual character from Iron Druid, just with the name changed. Then we had LITERALLY the Lucifer from the TV show, down to the “What is it you most desire?” Sure, Lucifer is public domain, but I doubt anyone could even muster a defense that it was obviously the tv version. Now in this book, not only do we have him meet “Henry and Murray” (Harry and Murphy) from Chicago, replete with “Hell's Bells” and duster references, but we have essentially Death from On a Pale Horse by Piers Anthony, with guest appearances by the rest of the Incarnations of Immortality. Again, public domain characters, but come on, you even stole the horse's name, Mortis!

Is this whole series going to be nothing but taking ideas that others have created and then twisting them slightly to encompass the Cthulhu mythos as well? (Yet another public domain series of stories that have been co-opted, of course.) Is this even legal? I feel like it would not be difficult at all to prove correlation here if a lawyer chose to, but maybe it is fair use or something? Can someone enlighten me? Because yeah it is cool at first to think, “Oh, he's talking about Dresden!” but then not as cool to think, “Huh, he literally stole the entire Lucifer character wholesale.”