As Hoffmann tells the stories of the three women he has loved, he gets progressively more drunk. That, combined with the fact that there are just some crazy characters he associates with, means that it's sometimes hard to keep track of who's who in the circus that is his life. So, we've mapped out the characters of the Tales of Hoffmann, as well as their relation to each other. As you can see, lots of artists appear in different incarnations in different acts.
There is discussion about whether the three women Hoffmann has loved are really facets of one woman, Stella, or if he's really just that unlucky with four different women. We have four artists in the four different roles, though occasionally one artist sings all four roles.
Despite the bizarre turns that Hoffmann's stories can take, there is still a certain pattern to his tales: he loves a woman, who is kept from him by a villain (all four villains are sung by Daniel Okulitch), and a valet who adds a bit of comic relief to the high drama.
The kind of love that Hoffmann experiences progresses through the acts however, as Ileana Montalbetti explained in this interview with Vue Weekly: "You see Hoffmann progress through love in each of the three stories. It's new, kind of fascinating love with Teiya's character (Olympia, the mechanical doll), and then ours (Hoffmann and Antonia) is very pure, very innocent and real, and then because I die, his heart is broken and he kind of moves into this sexual love with Giulietta."