First thing you should know about this achievement is that it is MISSABLE
. That being said, it is only around 2 or 3 hours into the game, so you won't have much to play through if you have missed it.
While it says you must defeat Deathstroke without failing a single counter, it might as well say "defeat Deathstroke without taking any damage", as pretty much every single one of Deathstroke's attacks will have to be countered.
There are three basic stages to this fight. Unfortunately it's nowhere near as easy as it was to defeat the Electrocutioner, as Deathstroke appears to learn your moves, and counters them himself if you use them more than a few times.
If you do end up taking damage, then you can simply pause and select 'Restart Checkpoint' from the menu. I did this many times!
The first stage is relatively simple, and essentially just like any of the enemies you have previously encountered, just a bit stronger. What I found to be a lot easier than attempting to counter every time was to double-tap
, which will make Batman jump over Deathstroke. Once you have done this, you are safe to land two or three hits before Deathstroke recovers, and will swing at you again. It's then a case of rinsing and repeating.
Once you have chipped away around three bars of his health, Deathstroke will drop a flash grenade, then launch at you. There's a QTE (quick-time event), where you have to mash
. It's relatively simple to complete.
Once this is complete, the second stage of the fight begins. Immediately after exiting the QTE, press
together. This will use your free-flow combo, which by this point should be at around x15. It will knock around a bar of health away immediately. From that point, repeat the same process as above: when he swings at you, double tap
and jump over, then hit him. While in the first stage you could hit him two or three times, Deathstroke seems to have faster reactions this time, so I'd only hit him once before jumping over again and repeating to process.
While this can happen at any time, it occurred for me during the second phase. Occasionally, Deathstroke will launch his Remote Grappel, which will attach to Batman and some nearby barrels, which will come flying towards him. It's not easy initially, but once you figure out the timings, you will be able to hit it every time. When it is flying towards you, press
(when the on-screen prompt appears) to catch the barrel. Then, press
to lock onto Deathstroke and
to throw it at him. This will knock a tiny amount of health off, so is not worth doing often. If you keep hitting / jumping / countering him, then he probably won't have an opportunity to use it.
When you get his health down about halfway, Deathstroke will drop another flash grenade, and you have another QTE to complete. It's just the same as last time, but a bit longer. Completing it begins the third stage of the fight, which is by far the hardest.
Deathstroke pulls out a sword, and behaves very unpredictably in this part of the fight. I would not suggest using the same techniques as described in the first and second stages, as this will likely result in you getting hit. Instead, your best bet is to try to counter him every time, and sneak a hit when you can afford to. Also of great use is the Batclaw Slam (
). This will pull Deathstroke towards Batman, who will slam him to the ground. It deals moderate damage. As mentioned above, Deathstroke will learn this if you use it multiple times, so throw in some over moves to knock his health down as well. Additionally, most counters in this section will require you to tap
three times, as indicated by the on-screen prompts, however I had a few situations where I only had to press it once.
As you work your way through this fight, knock little chunks off his health here and there, and counter whenever the prompt appears. Eventually, you will have another QTE, so just hammer
, then hammer
, and you will have completed the fight. The achievement will unlock at the end of the QTE. Additionally, if this is your first play through, you will unlock the achievement listed below.
This video shows you how to unlock this achievement, as well as showing you visually what you have to do should you be struggling with it. It is not an easy achievement, and took me around two hours to unlock!