i've been thinking about metaltango a lot lately, and what it is that draws me into that ship. in my experience a lot of people divide into two camps, very roughly the "Krauser was super nice but then went bad" and the "Krauser was always an abusive dick". which, each to their own!
personally though i like it when he's more complicated than that. to me, he starts out as a good guy, but with issues. he's not a perfect boyfriend who brings Leon breakfast in bed, but he's also not entirely violent and unhinged. he's rough around the edges, unable to talk feelings or show them much, but cares in his own gruff way. he's a bit too rough, a bit too impulsive, a bit too selfish. he definitely has anger issues. but he's also the kind of support Leon hasn't had before and would kill to save him in a heartbeat.
I enjoy it when things are complicated, when the relationship is both so bad for them and so good for them. it gives them both what they need while at the same time destroying parts of them. it gives Leon the chance to make (potentially bad) decisions about his life when all the other choices have been taken away, gives him the chance to feel something, anything. it gives Krauser companionship, someone who can match him beat for beat, someone who has an undying fire inside of him (and Krauser is a moth to that flame).
they'd burn bright and fast and it's probably always bound to end in a disaster. they'd both fall into it headfirst, damn the consequences, and end up hurt as hell for it.
this is also why I am so attached to the original versions of them because they're comrades, they're equals, they're two sides of the same coin and they are forever joined even when they're apart. they're evenly matched, even though Krauser likes to think he's in charge and Leon likes to let him.
...of course until they're on the opposite sides, when things shift. maybe it's the plaga slowly driving Krauser more unhinged, feeding his anger issues, or maybe it's simply the bitterness and resentment from how he was discarded after the injury. but something shifts. he lets the uglier sides to the surface more. even then it's fun to play with the idea that he'd hesitate before killing Leon, would regret doing so, but he's definitely a changed man on many levels.
Krauser has always been one of my favorites exactly for the complexity. he contains multitudes.
(and the necessary disclaimer: I'm not trying to tell anyone how to write him or see him! this is just my incoherent word vomit about the topic lol. and I sure as hell have also written things where he's shifted towards either extreme more just because sometimes it's fun :3)