This might be my biggest reader-ly booboo as I totally thought this was some kind of steampunk-y novel set during the historical demimonde (late 1800s, France) although to be fair, other than the title, nothing about this book should have lead me to that conclusion. Nope, I own this mistake and fortunately, it ended pretty well.The actual premise is that it is 2018 and the Demi-Monde is an online training 'game' for US soldiers to experience immersive extreme combat situations in foreign locales with factions headed by some of history's most violent, deranged, and methodical leaders. The game is self-learning, an active world of 30 million 'dupes' who continue to grow, shape, change, adapt, and evolve even when not in use. (There's a 'Product Description Manual' available for download from the book's website -- oddly enough, from option 9, 'Fashion of the Demi-Monde' -- which has some fascinating, nerdy details about the game world, factions, that kind of thing. I found it enormously helpful for understanding the world.)Most 'dupes' are just ordinary historical figures, but eleven are 'Singularities' -- the super insane, psychotic, charismatic, violent leaders from world history: Ivan the Terrible, Reinhard Heydrich, Henry VIII. Programmers designed the world into five factions, modeled on real world cities and loose exaggerations of cultural stereotypes, and created a nomadic people to increase tension so that there would always be conflict and war between at least two of the factions.This is a world designed for armed personnel, but at the novel's open, the U.S. President's daughter is scrambling around inside the Demi-Monde, trying desperately to keep away from the SS-Ordo-Templi-Aryanis -- a group that, even if you're not exactly sure who they are, is obviously very very evil -- as, for totally bizarre reasons, the primary currency in Demi-Monde is blood, and the dupes don't make blood. (Seriously, this book takes something from every genre and the kitchen sink, and weirdly, it kind of works!)The military wants to stage a rescue of the President's daughter Norma, but there's a hitch: the Demi-Mondians have started wondering about the random soldiers who show up now and then (in the Demi-Monde, Aleister Crowley has invited a pseudo-science that says real world humans are demons from another realm) and have sealed off entrances to the Demi-Monde. (I will admit I still have some serious fuzziness on how a computer game can 'stop' people from entering the game, but whatever.) So the military has to 'trick' the Demi-Monde into accepting their hero, an 18-year old high school jazz singer named Ella.Thankfully, Ella is as ignorant as we of the Demi-Monde, so the first few chapters explain all the world-building around the Demi-Monde, like why the world is centered around Victorian-era techonology(allegedly to replicate the kind of circumstances that US troops face when storming foreign locales), why it feels so real, who some of the factions are, that kind of thing.And here's where I get to some of the things that didn't work for me in this book, starting with Ella. For all this creative, elaborate world-building, the three lead female characters all super flat and dependent on static shorthand. Ella is a gorgeous, tough, sassy woman of color -- which is exciting -- but her main survival skill seems to be being too gorgeous for the villains to mess with. Her off-the-charts intelligence isn't reflected; in fact, she has a frightening lack of basic knowledge. Our imperious 'British' Demi-Mondian, Trixiebelle Dashwood, who flouts convention in the search for what she wants, remains just that, foot-stompy and head tossing, straight out of a romance novel. Norma, the President's daughter, alternates between being remarkably tough and annoyingly pathetic.After the heroines, I struggled with Rees' exaggerated Demi-Mondian cultures. One faction, 'The Coven', is basically an extreme man-hating-lesbian-feminist cult. As a lesbian and a feminist who doesn't hate men, it is one of my pet peeves when feminism and lesbians are twisted into this horrible caricature. Not that he singles out feminists and lesbians for this treatment: the Abrahamic traditions are twisted into an extreme anti-woman patriarchy, the Germanic/Tuetonic cultures are smashed into a crazy Nazi/Occult potpourri, the European joie de vivre and bohemianism of the 19th century has mutated into a hedonistic sex party. Subtlety isn't the thing 'round these parts. When I could get past my irritation, or, grew so accustomed that I no longer was bothered, I got lost in the very messed up world of the Demi-Monde.The end has a serious cliff-hanger, so I'm kind of eager for the next book, but at the same time, I really wish this wasn't a four book series. I'm exhausted by the Demi-Monde and Rees' use of random capitalization and acronyms -- I would probably take more time between books were I not scheduled to review the second book. (Speaking of the second book, I was super confused about the books as there seem to be multiple editions of these novels under varying names, but I think this book, the first, also goes by The Demi-Monde: Winter while the second book, The Shadow Wars, also goes by The Demi-Monde: Spring. I believe the third book has been released in the UK as The Demi-Monde: Summer but I haven't seen what the US release will be titled.)If you like dystopias, this is your book: it is a dystopia of dystopias. If you like Tron or The Matrix and big chunksters, this also is your book.