Can you explain how the backstab mechanic is different in the Souls games and why you think 3 has it best?
Easy.
Backstab works basically the same in Demon’s Souls and Dark Souls. If you’re behind the enemy, standing within a certain area, and press R1, then at that moment both you and the enemy will play a joint animation where you backstab him. During this animation you’re both invincible. It’s sort of like a 0 frame throw in old versions of street fighter. Oh, and you can’t backstab if your shield is up.
This meant that backstab, no matter what weapon you had, was essentially instant and inescapable. Your only defense was preventing the enemy from getting behind your back at all. Backstabs were more powerful than regular attacks, so a lot of PVP was just about backstabbing and avoiding backstabbing.
In Dark Souls 2, they decided to mess with backstabs a little. Instead of instantly going into the combined animation where you’re stabbing them, they gave you a little punch animation first. This punch was unblockable and would cancel on hit into the full backstab. If it missed then nothing else would happen. This is a bit more like a modern fighting game throw. You have a chance to roll out or walk away before getting hit by it. This significantly reduced the role of backstabs in PVP, while keeping them viable. Backstabs were still really powerful in PvE however. Also from a thematic standpoint it’s kind of weird that you punch the guy then stab them, didn’t really match the prior games.
In Bloodborne it seems like they REALLY didn’t want anyone to fuck with backstabs at all. In order to get a backstab, you needed to charge your R2 attack all the way up and hit the enemy in the back with it, much like the positioning for backstabs in the other games. Then they’d become vulnerable and you’d get to do the 0frame throw thing for a ton of bonus damage. So overall you were getting a lot more damage out of successful backstabs in bloodborne, but it was a lot harder to set them up mid-combat, and they were now basically completely irrelevant to PVP.
In Dark Souls 3, they clearly wanted to have backstabs match demon’s souls and dark souls 1, and to do this they assembled a mechanic that’s practically a work of art. Basically, when you press R1 within the activation range, instead of directly entering a joint animation with the enemy, you’ll instead play a specific backstabbing animation. If the enemy stays close to you, then at a certain point in this animation, there’s an invisible unblockable hitbox that comes out that forces them into a joint animation with you, canceling whatever they were doing, and canceling your lone backstabbing animation into the joint backstab (using animation blending). If they aren’t in range of this hitbox, then you’ll just continue to play the lone backstab animation, which functions as a regular (slower) attack basically. So you smoothly either get a backstab or just stab without needing to punch them first like dark souls 2, and without an instantaneous startup like DaS1 and DeS.