On the other hand 'Jack of Shadows' takes place in a world so drastically different from ours that it doesn't even begin to make sense until about fifty pages into a 200 page novel. This is what I love about Shadows, Zelazny has gone for broke creating this universe, imagining a place where science and magic can both inhabit the same area, and in the place of the planet's core become each other's imagined fear. This is great stuff. But, compare the characters of those other series with the characters of Shadows and you'll come up short. With the exception of Morningstar (probably everyone's favorite character, and the demon in the picture above) all of the characters in the novel are someone we've all encountered before in Fantasy and SF.
Even Jack's incredible powers seem commonplace now. Though I'm not sure how they might have been viewed in the 1970's, I'm pretty sure I've seen cartoon characters that can transport themselves by shadows. It's one of the problems of reading older fiction, you can never tell if a given trope is itself a cliche, or the original that all other cliches are based on.
Aside from Morningstar there is Jack, who fits the mold of revenge seeking loner so neatly that I don't really need to go further into detail for you to understand him. There is his enemy, the Lord of Bats, really a stock magician whose only shining grace is locking Jack into a 'room without doors,' another interesting piece of world building by Zelazny. Jack's betrothed Evene is almost an afterthought as far as character development is concerned, though Jack's own manipulation of the character could be considered partly responsible for that.
The one truly great point that Zelazny makes with his characters is to send up the idea of a classic hero. This is a bit of subversion that still feels original and fresh now forty years later. The reader begins the novel sympathizing with Jack, we do see him killed on the first page after all. As Jack continues on with his quest we see him do horrible things, all forgivable and most understandable, but nonetheless still horrible. He continues on with his quest and maintains reader sympathy until somehow we arrive at an end in which Jack is undoubtedly a terrible person, beyond sympathy, completely friendless but for Morningstar.
It's only at the end of the novel in which we realize that though Jack is surely the protagonist of this novel he can in no way be called a hero, and might even be the antagonist of the very same book. Zelazny has a habit of creating antiheroes bound for revenge but he really outdoes himself here, and Jack's not so much bent on revenge as he is on absolute destruction of anyone who has committed the smallest slight against him. It makes for an interesting read when you arrive at the end of the novel to find that Jack has slowly progressed from lovable antihero to despotic ruler of half a planet, and ultimately to destroyer of an entire civilization.
Normally I dislike books that end on the sort of 'Lady or the Tiger' ending that Zelazny has here, but I didn't mind it in this case. Zelazny gives us the knowledge we need about the future of Morningstar, freed from his eternal prison by his finally seeing the sunrise, and tells us what we need about Jack's future. Namely that he is willing to give up being a ruler, and accepts whatever might come in the new world he has created. Zelazny lets us choose which ending we like, does Morningstar catch him or not? Ultimately I don't think it matters though, even if Jack lives we have seen how the this world works, and Jack will forever be marred by the actions he took while in possession of the Kolwynia, no one will forgive him and he has affected everyone. He will be a pariah on both the light and dark sides of the planet. It does not matter if Jack lives or dies, he's made his choices and will have to live (or die) with them.