30 years ago - Victor Zsasz is born.
10 years ago - 20-year-old Victor's parents are killed.
9 years ago - 21-year-old Victor loses everything in a poker game with Oswald Cobblepot. He kills for the first time, making the first cut on his body.
4 years ago - 26-year-old Victor is freed from Arkham by Bane, he takes over a catholic school and stages a hostage situation.
3 years ago - 27-year-old Victor escapes from Arkham again during No Man's Land and nearly kills Alfred Pennyworth before he's saved by Cassandra Cain, the only mark on his body without a corresponding murder
Zsasz has become a major player in the list of Batman enemies but he's very deliberately not meant as one of his main nemesis. He's simple and easy to understand narratively while still presenting a major challenge to the hero. He's a character that's MEANT to spend most of his time locked up. The visual of his body covered in slashes representing all his kills is utilitarian but functional, and he's JUST interesting enough that we can listen to his psychotic ramblings for a page or two before his inevitable defeat. This is a real meat-and-potatoes comic book badguy, and clean addition to the underworld of Gotham.
Zsasz's Comic History
Zsasz was created by Alan Grand in 1992; and it was hard to argue with the concept. While every other Batman villain, even the lethally crazy ones, are busy crafting an elaborate scheme to trap or confound Batman while exhibiting the nature of their particular psychosis, Zsasz just gets about the business of killing people, making any story featuring him a race against time. This was at the height of the 'gritty 90's', when every comic needed to be as dark as possible, but what you wound up with was a very story-first character with minimal design fluff that just gave you a very functional threat for simple easy-to-digest stories. He fit in with all the other Gotham psychopaths, he just didn't beat around the bush with it.
This simple concept has been very easy to adapt to a wide variety of formats. Any time a Batman story needs a ready-made villain with minimal complication, Zsasz seems to be the one they go to. He was used very well in the Gotham series as a mob enforcer, appeared as one of the prisoners in Batman Begins, and was featured in his own series of sidemissions in the game Batman: Arkham City. While his own stories might be pretty basic affairs, his role in the larger tapestry of Gotham is well established.
Our Zsasz Story
For Zsasz to really pose much of a threat he needs to be pretty physically intimidating, so while he is sometimes depicted as a scrawny creepy dude, he makes more sense if he looks like a real brawler with no compunctions about murdering his enemy in any way possible. It's hard for a character to really make much of an inpact with just a knife in a world that includes power rings, so Zsasz needs to be basically uninterested in interacting with superheroes, instead going out of his way to simply prey on ordinary people.
One of my favorite Zsasz stories features his attempt to kill Alfred, only for him to fight the mass-murderer off. It's essentially understood that Alfred is way more badass than he looks, and Zsasz is a great bad guy to use to show that. We ultimately made that story part of No Man's Land and used it as Cassandra Cain's in with the Batman family, but the notion of a protracted battle between Zsasz and Alfred is still something we totally love.
As we've said, Zsasz's role in the larger story is pretty much set. We understand who he is, what he does, and what's going to happen to him. If we wanted to, he could simply stay as he is and the story could happily churn forward as is.
However, there is another way to look at him. He's not a complex character, but he is interesting enough to imagine that there might be more that can be done with him. He could, for example, be the basis of some larger story, perhaps where he becomes tied into a larger narrative that grants him some sort of power, creating a new villain that is incredibly dangerous, someone that would require a larger group of heroes to stop. The immediate idea that pops to mind would be him gaining some sort of demonic power. That would be a story that might require the Justice Society or even the League itself.
This is just conjecture... we didn't include anything like this into our timeline as it stands. For now, he remains a lethal threat to Batman, but one that is usually locked up. Still... all it really takes is one good writer with a really good idea.