These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Canon Sue: Caesar can verge on this; of course, with a historical figure who did accomplish so much, it's difficult to tell where to draw the line.
Complete Monster: Quintus Servilius Caepio starts by stealing a fortune in gold that legally belonged to Rome, having several hundred Roman troops murdered by bandits to conceal the identity of the thief. Then he causes the worst military disaster in Roman history because, coming from an immensely aristocratic background, he considers himself above working with the lowborn consul appointed to fight a massive barbarian invasion. Caepio survives the battle by stealing a boat and abandoning his entire army to their deaths.
Evil Matriarch: Servilia to Brutus. Servilia may be the most ambitious character in the series and Brutus is rather...mediocre, to be kind. She does a lot of despicable things so she and Brutus advance in Rome. And she's also just kinda cruel.
Fridge Brilliance: If you get annoyed at the Mary Sue depiction of Gaius Julius Caesar, you might eventually realise that the story has been written in the form of propaganda written by Augustus. It was entirely in his advantage to present Caesar as a Mary Sue, and depict all of his enemies as bickering petty men.
God-Mode Sue: Caesar is smarter, tougher, stronger, braver and more morally decent than anyone else in the books by a ridiculous measure. In line with the Deliberate Values Dissonance, though, he really can't see anything but Roman traditional values.
Squick: Cleopatra reflecting on sex with Marc Antony, specifically in reference to the size of his manhood, and how "he would have hurt her, had she not given birth to Caesarion." Think about it.
Tear Jerker: Plenty: A lot of sympathetic characters die young or violently. Cato's crossing the Libyan desert (and seeing visions of his long dead brother and mother, both of whose fates are very sad in themselves) is very moving.