The number of characters in a relatively long novel tend to proliferate. Especially when you have multiple narrators and action in two or more settings. The challenge is to differentiate the characters. We have all read books were the one thousand female characters are really only about three people (you know of that of which I speak). 

The first step in this is the easiest. I give my characters quirks: Marcus is forever bothered by that mural in Varus’ office (the one with the sun setting in the east), he always makes his dislike of Praetorians known, and he is always willing to talk about architecture; Septimus has a thing for how people smell and is always pointing out the deficiencies in peoples security measures; Mistral is always resisting the urge to slap her commanding officer. After that it gets a bit more subtle. 

As some characters grow up together, I give them similar traits: Timolen and Marcus are both reserved (Timolen so reserved he gives nothing away), they have a similar sense of humor, are both experts at getting the last word in an argument, and the only person they ever divulge their defining childhood trauma to is not their closest friend but a woman (different woman in each case). Others I contrast. I have two princesses. Antonia’s mother is the youngest daughter of an Emperor, her father was the Savior of the Emperor, the current Emperor, her uncle, has no daughters and she is his only niece. She also has three older brothers. Antonia is the most privileged young woman in the richest empire of the world – she is a brat – just not a stupid brat. She realizes from a young age that she lives in a gilded cage and is just a pawn to her powerful family – she is desperate for power. Isolde is the youngest child and only daughter of a Celtic King. Her kingdom is small (relatively wealthy) well-guarded but isolated. She too realizes what her family plans for her (she refers to herself as a Prized Heifer) but is resigned to her fate. Isolde just hopes for a dashing warrior prince instead of a monster for a husband (she gets neither). When her new husband sends her out among the commoners to get things done, she is out of her element and terrified (that actually plays well with her subjects); Antonia in contrast revels in her freedom (perhaps she wanted freedom not power). Antonia is an annoying, people person that is very sure of herself; Isolde the opposite. 

I also draw sharp distinctions between those that command and those they command. Marcus is referred to as Captain Serious; his Legionnaires are either joking, arguing, or wagering on something. Marin and her daughter Mistral are serious characters (Mistral can best be described as intense); the other Anemoi are anything but. For example, the Tribune Max gauges the seriousness of the situation by how many sexual innuendos his Anemoi scout puts into her report.  

Characters coming to understand the people (sometimes very different people) around them is a central theme of the novel. From Antonia realizing just what her grandmother Drucilla is capable of to Mistral admitting that Captain Serious can actually sometimes be human to Bri realizing that she is more likely to chase the monster from her childhood nightmares through the forest than the other way round (let’s face it it’s the women making the effort – for the most part men just take you as you are). In any case I hope I’ve made my forty odd characters distinct and interesting enough for you, the reader. I put in the effort.