Killer Croc - 

The first very boss in Batman Arkham Origins is the Killer Croc. Since he is the first boss, it takes things easy on you.

Croc is simply gonna throw things on you and attack.Its very simple to dodge them or distract him by throwing some Quick Batrangs on him (Double tap LT for Xbox).

He will sometimes try to bite you..But its easy to pound off.

To beat him you will have to use stun by throwing cape on him three times.(Tap 'B' for Xbox)

Death Stroke - 

The next boss in Batman: Arkham Origins is the Deathstroke. The main point in this battle is that. You have to concentrate more on counter and dodging then simply going aggressive. There are three phases of fight.

The first phase:

In the first phase it will be okay to be aggressive.But using the same attacks over and over will make Deathstroke counter them. Don't hit more than 3 times the same attack. You can use Batrangs to distract him. Once the health is bit low..There will be a flash and then you will have to actually smash the counter button followed by a beat-down which will remove his helmet/mask.

The second phase - 

During the second phase I recommend not to attack more than two times and concentrate on counters. Here he might also hit you with a cylinder.To counter it face the side on the cylinder and once directly in front of you smash the counter button and face it to Deathstroke and release.In this phase I recommend using the Bat Grapple and simultaneously pressing the attack button to beat him down. Once again the screen will flash and you have to smash the counter button followed by attack button.This time you will be breaking his stick taking the battle into the last phase.

The final phase - 

In the final phase Deathstroke will use a short knife.If you attack him more than thrice you will have to counter his knife. I strongly recommend in this phase to counter maximum times and attack hardly once or twice. Bat Grapple is very useful and batrang to distract him. When prompted throw him and attack him a couple of times. This will be followed by a cut scene and in no time Deathstroke will be defeated..

Copperhead - 

You might be thinking it's gonna be so difficult as Batman's dazed off and stuff.But according to gaming logic he is back to normal in the fight. Here there are dozens of Copperhead(s) pouncing on you.The only way to clear them out is combat streak or a I recommend quick fire explosive gel ( Press LT and Y for xbox)

This will blow up the fake Copperhead and the original one will be dazed off. Once you get the original one feel free to attack.Once her hp is almost half. She will pounce on you at speed of lightning which you have to evade at all costs.Here also use explosive gel and once got the real one blow her up...After the hp is very low there will be a cut scene where you will be getting the anti-diode from Alfred making it end of the battle.

Firefly -

Once you diffuse all the bombs, Firefly appears..This fight will take place at different places all over the bridge through wreckage,flames and all bricks etc. In the first phase...He is going to use Flamethrowers..There will appear a red line above him letting you know when he will be firing.Once he stops it feel free to throw some batrangs(Double tap LT for xbox)..I recommend using Glue Grenades(Double tap RT) as well making him immobile and then you are again free to throw batrangs...Once he dozes of use Bat Grapple and pull him..

Next you will have to run..Go from under the truck..

Here he will use some lasers and bombs..You have to follow the same principal as in before cases..GlueGrenade - > Batrang ->Bat Grapple.Once Firefly's health is real low,there will be a cut-scene where you have to grapple him.Then he will make you go through various obstacles like poles,flames etc.You have to counter them.There will be one more cut-scene where you defeat Firefly...

Bane - 

There are two encounters with Bane in Batman Arkham Origins.The first is in the Hotel and later in the Black Gate Prison.Both have almost the same combat technique.

First encounter -

The first encounter will take place in Penthouse in the Royal Hotel.Once you enter the penthouse there will be a cut-scene with Joker and Bane.Then the fight starts.

Phase 1 - 

When Bane is in his normal mode, you have to only counter and then attack him. That's all that has to be done in the first phase.When he injects poison,simply evade his attacks and wait until the gloves are charged and then take out his poison.There will be a cut-scene where he will throw you out of the window and you will have a short talk with Alfred. 

Phase 2 -

The next fight will take place in the balcony like place. The bane here will rush to like like anything. The only option here is to evade when he is real close or evade will fail.After some time his mercenaries will come and pounce upon you. Counter them and Bane both.When the arena is clean feel free to beat Bane.When he is in his poison mode evade and when he uses jumps in the center go and use Stun on him.Then take him down.

When Bane's health will be real low, there will be a cut-scene of Gordon coming thereby ending this fight.

Second Encounter -

The second encounter will take place in Black Gate Prison.Here you have to use the same tactics as before, but here there will be more enemies pouncing on you.

Phase 1 -

In this phase do the same as before, but concentrate more on counter and evade then going offense.There will be not much time and Bane will be in his low health.There will be a cut-scene here where you have unlimited access to Shock Gloves now.The aim here is to simply attack him and evade.Then again a cut-scene where you stop Bane's heart to save Joker and Gordon.

Phase 2 -

Then you will activate his heart using the gloves like Alfred's.Once done, there will be cut-scene where Bane will inject TN-1 poison taking the battle into final phase.

Here you must hide in grates.Electrical doors are the only way to take him down.Get near the electrical doors and when he comes use the Take-down button to smash him into the door and then followed by a beat-down.Once done quickly evade before getting into grates.If he sees you in grates he will take you and destroy the grates.After a few take-downs there will be jammer which you can chose to disrupt or go on with your normal senses.Once only one health bar is left, you will be talking to Alfred and then Bane grabs you and throws into the other side.Here you have to use Deathstroke's weapon by pressing LT(xbox) and hereby ending the fight with Bane!