Honestly I think that one of the main reasons for the animosity between Mercymorn and Augustine, aside from what happened with Cristabel and Alfred and simply not having the most compatible personalities, is the radically different ways they handle their grief, their emotions generally and their immortality. Augustine is all carefully cultivated charm, hollow humour, a genteel mask of nonchalance and elegance. Very fifth. And as Harrow points out, its all farce!! This man is an empty shell!! He avoids any earnest emotion, any genuine affect, like the plague. Now, Mercy is the stark opposite - she’s all affect, all earnest emotion. She looses her composure, she says what she thinks. She’s almost painfully blunt.
And I think they absolutely hate each other for how the other handles their grief, general emotions and life situation. I think Augustine is repulsed by how terribly earnest Mercy is - she carries her bitterness, her immeasurable grief, her fury and hate, on her sleeve. No filter, no mask. Mercy who yells at John, Mercy who flies into a rage at the mention of Cristabel, Mercy who never even attempts a personable, charming facade. Augustine cannot stand this - perhaps he resents her for how cathartic her approach seems to be, compared to his. She can be a fine enough actress, he knows, so why can’t she put any effort into suppressing her emotions like
hima normal person? Now, Mercy!!! She explicitly reacts upset at Augustines carefully crafted compartmentalisation, his fake cool composure. She’s irate that he has gone through the same pain and grief as she has and yet plays at being so cool and unaffected over it. How dare he! How dare he casually talk about their cavaliers so calmly and jovially! Mercy is done masking her grief, her anger and frustration, done with making herself likeable and palatable. And yet Augustine made exactly that his whole personality, and it seems to work, at least on John. She is repulsed by his cooler-than-you attitude, which makes her seem emotional and unrefined next to him.I have way too many thoughts about these old bastards