Batman Arkham Origins
Deathstroke dissapears while fighting him Solved!
Deathstroke bug/glitch Fixed!
Batman Arkham Origins Deathstroke boss fight Solved.

How to beat Deathstroke in Arkham Origins. If like me you just go ahead and try and kick his ass using the bat claw or just fighting at your own pace at some point during the battle Deathstroke will vanish out of the game all you can do then is restart the game. I had to do this about 10 time then i realised how to beat him easy every single time without him disappearing.
Play the game how the developers intended boring but you have to do it the game has to play in a sequence of events that can not be rushed. This means you need to play slow defend and counter at the correct times and avoid using the bat claw.
If you do this you will beat Deathstroke easy and you will win his weapon. XD If i get a chance ill record me beating him this way.

Hope this helps you guys i know lots of people who can not progress no further in the game because of this bug/glitch poor coding? Batman Arkham Origins