For this round, I chose wrath, cause from the moment  I saw that we'd be doing the seven deadly sins, I was like
dude
cain and abel

so ye this is my take on a more modern-day cain demon thing

long story short, cain and abel were adam and eve's sons. cain was a farmer, abel was a shepered. when god was bein all like "yo sacrifice your firstborn lambs to me", abel did just that, while cain decided, since it'd be easier consideringhow he was the farmer, that he'd offer the best of his crops. this made god mad so cain was mad and everyone was just sorta mad. and then satan shows up and is like "hey there kid, I know how to solve aaaalllll your problems. ya just gotta kill your lil bro over there and everything will be a-ok."
somehow cain fell for this.
he ended up stabbing abel with the jaw bone of some poor ram or sheep or somethin, and surprise surprise, god comes and asks what happened to abel. cain just sorta pretends he doesn't know what happened, but I mean, cmon, this is friggin god, he knows all the things ya moron. so, cain is cursed with the ability to not die prematurely, or in other words, no one can actually kill him (though in some versions of the story he gets killed bby the first blade, and in others he's crushed by his stone house cause he's smart like that).
so, yknow, this could have all been avoided if cain hadn't been so dang mad that he couldn't follow one simple order and kill a lil baby sheep. I don't know about anyone else, but I think it's fair to say that cain's deadly sin is wrath in this senario.

that's pretty much why I chose to do what I did, I hope you enjoy ;v;