Backstabs are one of the most powerful attacks in Dark Souls, letting you disable an enemy while inflicting huge amounts of damage. It became so popular From Software nerfed it for Dark Souls II, but it seems to be back in action for Dark Souls III.
One of the love-it-or-hate-it pieces of the Dark Souls formula is the game's reliance on strict animations. (This is sometimes called "animation priority," as it lets the animation play out before the player can input another action. Many games let you interrupt animations.) A backstab stops the action for a brief moment, and you feel like a bad arse while doing it.
In Dark Souls, backstabs were very simple. A common strategy was to use the game's lock-on to quickly get behind an enemy (or player) and watch the animation kick in with little effort.
(Thanks to Phtantom EWGF for the clip!)
When engaging in PvP, constantly going for this attack is called backstab fishing, and there are whole videos dedicated to countering what many high-level players consider a cheap tactic. It also made fights boring; people would spend their whole time circling around one another.
Often, the best tactic was to counter backstab, as pointed out by redditor genzahg:
The consequences of getting backstabbed were dire, and were only exacerbated by the original game's lag issues. In some of the worst case scenarios, you'd suddenly die out of nowhere.
Even though it was possible to deal with backstab fishing, many fans felt it was incredibly detrimental to the PvP community. From Software seemed to agree, which is why backstabs became far more complicated with Dark Souls II.
For one, they no longer made the player invincible. In the first game, pulling off a backstab not only damaged an enemy, but briefly shielded you from anything else in the world, even if the attacks connected with your character. This was no longer the case in Dark Souls II, in which players were both vulnerable and backstab animations were much longer -- it was a huge risk.
In Dark Souls II, there's a brief window where a player can escape a backstab by rolling, so even if you're caught by surprise (or someone is backstab fishing), there's options. Secondly, the window for pulling off a backstab changes based on the weapon, so it's not just a matter of rolling up behind someone, tapping R1, and watching everything start going your way. From Software also reduced overall damage most weapons inflict with a backstab, meaning regular weapon combos often made more sense. Several items straight up nulled backstabs.
It didn't solve the backstab problem entirely -- there are loads of players who'd rather see the mechanic removed from multiplayer, if not the entire game -- but it tried to address the issue.
Which, of course, brings us to the latest game, Dark Souls III. From Software hasn't explicitly talked about how backstabs work in the latest sequel, but let's take another look at this GIF:
That backstab happens incredibly fast. It's impossible to know how wide the window is for pulling off a backstab without playing the game ourselves -- we're not at Gamescom, sadly -- but we can try to infer a little more by looking at gameplay videos starting to trickle out.
IGN has 16 minutes of Dark Souls III gameplay, which includes a backstab at the seven-minute mark. It wouldn't be a surprise for an official trailer to have a Dark Souls expert pulling off killer moves, but it sure looks like this player pulls of a backstab rather effortlessly:
Again, it's a little hard to tell.
There's also speculation that maaaaaybe the game is taking the series back to its roots, Demon's Souls. That game also had an incredibly fast transition between attacking and backstabs:
(Thanks to Oleksandr Dunayevskyy for the clip!)
To be honest, I'd be OK with backstabs getting removed from the Souls series, or at least cribbing how they were modified for its sister game, Bloodborne. In Bloodborne, you couldn't pull off a backstab without getting behind an enemy (or player), holding down R2 for a hot second, and putting them into a brief stunned state. You really had to work for the backstab, and there was no chance a player was going to pull it off without putting in serious effort.
If Dark Souls III is like Dark Souls II and Bloodborne, there will be a beta test sometime before the game's release. We only know Dark Souls III is coming in "early 2016", so it's possible we'll have some more clarity before the end of the year.