The other Mann: Klaus Mann's novel about the Nazi atrocities

A different Mann - Klaus (forever unfortunately to be known as Thomas's son) - is much less known than famous father but has emerged recently thanks to a new bio of this guy whose life sounds movie-like - gay, addicted, literary, troubled family, contrast w/ father who was closeted, exile, opponent of Hitler, endangered species, died too young - and maybe will become a movie who knows? Inspired by a review of the bio, I am reading K Mann's best-known novel, Mephisto, from 1936, in German (I think K Mann later wrote in English?) and the first chapter itself is amazingly brave and prescient, an account of a huge Nazi party gathering (set contemporary 1936 - seems it could have taken place at any time up to about 1944) to celebrate the anniversary of one of the party big-shot monstrosities married to a movie star. Obviously each of the people introduced at this party scene is based on someone in contemporary German society and in the Hitler hierarchy. I can't ID them; an annotated edition of this novel would help but probably isn't necessary as we get the picture: these are horrible people with no values other than survival and blood-lust, more obvious to us today looking back than it would have been necessarily in 1936. The center of the novel is the eponymous Mephisto (stage name), who is the young, ruggedly handsome, recently appointed director of the national theater. His appointment is a bone of contention between his patron, a military leader, and the perverse minister of propaganda (Goring?). The first chapter, called the Preface, just sets up the characters and the mood of the time - lots of lavish celebration at party, that is at the public, expense for the insiders "fortunate" enough to be invited to celebrate this travesty of a marriage; the plot is not yet under way - but I think it will have something to do with people who claim to be Nazi opponents but are in fact collaborators. Mann's bravery in writing this novel, wherever he may have been living, in 1936 is evident - there wasn't to my knowledge a lot of literature in the 1930s that truly exposed the Nazi horrors.