I've noticed recently that Slade's father is mentioned quite a few times in some of the older comics, but it's always done briefly and always as a side comment. From what one can gather even from what little that has been provided, Slade's relationship with his father was anything but positive, and even more so because he's rarely talked about. In fact none of Slade's own family have ever been introduced, like a mother, siblings, grandparents, ect. (Unless of course you count Frannie, and Slade's half-brother Wade Defarge). So what is the real story behind Slade's elusive family and past. Why has there never been any kind of back story about Slade's childhood, past, or family history?
Of course like most villains, as Slade is often characterized, the subject of family and childhood memories (all that gushy stuff) isn't generally important to such characters. You either hate him for being a villain, or you love him for being bad. Except that Slade's character has been more widely viewed over the years by fans as more of an Anti-hero than a villain, always bordering on the edge of good and evil, which I find to be one of his most intriguing qualities. In many ways he's very similar to an Old Western outlaw. He makes his own decisions based off his own judgments; he takes jobs and kills those he deems worthy of justice or revenge, his world is based on honor, respect, and reputation. But just like any good western, Slade needs a good back story to help explain how he got here, why he does the things he does, and what motivates him to keep his code, to stay solo, and to keep fighting for the things he believes in.
However, even if Slade is a villain, this still shouldn't be an excuse for this blatant absence in character development. To help explain, let us look at another of DC's most notorious villains, The Joker. Though downplayed as the delusions of a madman, The Joker's past has been explored, in multiple ways even. But imagine if the Joker's back story was never postulated, there would be no story about a vat of chemicals, there would be no red hood, or supposed tragic story of a murdered wife and child. There would be no washed up comedian or devilish child who burned down the house with his parents still inside. All these stories make the Joker all the more tantalizing, and attractive, without them can it truly be said that he would be the same clown prince of crime that is so loved and embedded in pop-culture today? When it comes down to it everyone knows a good back story strengthens a character, It's what makes us love them, even those characters that were created to be hated.
Then again, this isn't to say that Slade has never had a back story. There has indeed been a large amount of character development and history with the family Slade has made for himself, with his children, Grant, Joseph, and later Rose, as well as with his wife Adeline Kane, and even with his best friend Wintergreen. And sure we know about his life in the army, where he was practically born and bred, but why not push that further? What happened before that? What made him run away at such an early age of 16 and want to join the army? What did he leave behind? What ghosts from his past still haunt him to this day? As a fan, I can never get enough of Deathstroke. I love his character. But the subject of his own personal history, his own family could be explored a whole lot more (even in flashbacks or a one shot.) Especially in the new 52, when now it seems his character is being completely re-written. If done well, this could re-define Slade's character exponentially to better places and make for some great, memorable stories.