Ooh, this will be tricky to write in a spoiler-free way, but I'll try.

the character I least understand

Probably Sulien. I mean, Romanitas is a series with a huge emphasis on characters' interiority, so it's not as if I don't know what he's feeling and thinking, and what motivates him. But it always baffled me that he wasn't angrier about what had happened to him, and how oblivious he was to the fact that he was a slave, and that everyone around him viewed him as such, and how uncomplicatedly cheerful he was all the time, given his backstory!

interactions I enjoyed the most

Unsurprisingly, I love, love, love every moment Una and Marcus interact. I love their tense, prickly awkwardness. I love Una's initial scorn for him, and the fact that she never lets him off the hook for his privileged existence. I love that both are intensely private people who find it hard to talk to others, hate being touched, and are just incredibly introverted, and the sense of common ground they find with that.

the character who scares me the most

Drusus. He absolutely terrifies me.

the character who is mostly like me

I identify a lot with Una, although obviously I've never been through anything as terrible as she's experienced. I also sympathise a lot with Makaria's prickliness, and her desire to just be left alone on her island, but I feel I'm a bit more emotionally expressive!

I also feel like I have elements of Varius and Cleomenes, especially their tendency to look on ruefully and in horror at the various disasters they're dragged into by Marcus, Sulien and Una. I get the feeling Cleomenes would just like a quiet life, but his conscience won't allow it!

hottest looks character

I don't know? I have very strong mental images of the characters, but I think the ones I think are attractive are only in the later books.

one thing I dislike about my fave character

She, like me, tends to be very controlling, because she doesn't trust anyone else to get things right to her exacting standards. I guess it's understandable, given she spends most of the first book fleeing for her life, and then hanging out with others who are hiding in fear for their lives, and then stopping a conspiracy — the stakes are so high!

one thing I like about my hated character

Ummmm, Drusus is very good at being the fictional embodiment of everything I hate and fear, so he's the absolute perfect antagonist?

a quote or scene that haunts me

The moment when Marcus saves Una from kidnapping in Wolf Step, and her gratitude is all bound up with complicated feelings of shame and contempt. Also the scene in the greenhouse — it's just so beautifully written, such an evocative scene that you can almost feel the steam and the water (and ever since I've wanted to go swimming in a greenhouse).

a death that left me indifferent

I don't really think there were any? Maybe the spy sent to find the camp at Holzarta, who Una and Dama drive away and trick and kill? He's a bit of a plot device, so that readers can witness Dama's ruthlessness, and we don't know enough of his personality to really feel much when he's gone.

a character I wish died but didn’t

This is kind of a spoiler...

my ship that never sailed

The only thing I ship in the first book is Marcus/Una, so I don't really have an answer for this question, since the ship I love intensely get together by the end of the book!

For once my Una icon is fandom-appropriate for the comment to which it's attached!