It's not a perfect translation, but 'terriculum' is meant to be something like terror-smith, because Latin didn't have any fitting words for gunsmith. Somehow it just struck me as funny to see 'terriculum class' with that in mind.
It may sound sadistic, but I rather enjoy just how strained and haggard Deni seems in this collab. It's clear that the guilt is eating him up inside, and the single-minded obsession with forging a physical apology is something that goes a long way toward redeeming him. Only Ignis can take that all the way, though. I'm rather invested in seeing how the pair comes through this trial, as one of the longest-running relationships in the history of our little RP-verse. Flawed but believable.
Aeria had what felt like a minor role in this collab, serving as something of a sounding board, something for Deni to bounce his thoughts off of. That's not inherently a bad thing, but it does leave me with little to offer in the way of commentary. Aeria's tough position as a friend to both parties kind of ties her hands and limits what she can do without alienating one or both of them. That part feels like it shows well.