The first volume of Shelley's Last Man provides a unique context and setting for one of the first apocalyptic tales. Like Brian, I was also stricken by the strange temporality that Mary Shelley posits as the future. The setting is largely unchanged from the world that Shelley could have observed outside of her own window. This decision causes me pause as a reader. Such a blurred boundary between reality and fiction (particularly when that fiction is supposed to take place centuries after the novel was written) suggests that Mary Shelley was purposefully constructing a novel that read very similarly to other romantic era dramas. This furthers the forced comparison of Shelley's world and the remarkably similar apocalyptic setting.
The characters are also alight with the passion that Shelley's friends and loved ones were known for. Lord Raymond is clearly meant to represent Lord Byron, a close friend to both Percy and Mary. This is reflected by Raymond's military interests in Greece as well as the vivacious personality that he and Byron purportedly shared. Adrian is a beautiful homage to the kind, intelligent spirit of Mary's husband, Percy. The incestuous nature of their friend group (Raymond, Adrian, Verney, etc) is also rather reminiscent of the entangled relationships shared by the author and her literary pals.  Clearly, the absence of Shelley's late husband and her close friend are weighing heavily upon Shelley's construction of our end-of-days. Interestingly, the same fellows can be thanked for Shelley's Frankenstein. Their company inspired a contest in which Shelley invented the tale as a ghost story offering. So, as they were a part of Mary's literary monster, it would be a fitting memorial to allow their passing to inspire her for her literary construction of our collective demise.