Even though combo breaking is difficult and risky for the defense, and even though failing a combo breaker attempt leads to good damage on average, the concept of combo breaking is still lacking a key component. There needs to be a looming threat in the background, that even though you’re able to break, there may be times you don’t want to. If an offensive player in Killer Instinct predicts a combo break attempt, he can take full control of the situation by using a counter breaker.
When you have entered the combo system (that is, when you are performing any attack that can be combo broken), press MP+MK at any time to perform a counter breaker. You will stop the combo immediately and enter a very punishable counter pose, similar to a shadow counter. If the opponent attempts to combo break with any strength while you are in this pose, a counter break occurs. You will hit the opponent with a giant energy blast and immediately re-enter the combo sequence with 0 KV, and your opponent will be given a purple lockout which lasts for 4 seconds (1 second longer than timing or strength lockouts). You should take advantage of this 4 second lockout to hit with your most damaging combo, which for most characters will be well over 50% damage even with no shadow meter spent. If the opponent does not try to combo break, you will instead be left fully vulnerable directly in his face, and he can capitalize by starting his own combo.
Counter breakers are the strongest offensive read possible in Killer Instinct, and can only be done in anticipation of a break attempt, not on reaction to one. Counter breakers are never safe to attempt, but they lead to the most damage possible in the combo system, and the threat that the offense can counter break at any time will make defenders perpetually nervous. They are also very satisfying to perform; the announcer shouts loudly, the screen zooms in for the defender’s punishment, and then you get 4 seconds to perform heavily damaging normals and specials. It accentuates the emotional high or low of doing the right or the wrong thing in a fighting game extremely well, and the satisfaction of planning a counter breaker and being correct is one of Killer Instinct's best feelings.
What should you do when you land a counter breaker? You should immediately transition into your character’s damage loop, which is a fairly easy-to-find 4 second combo that does the most damage. I've outlined each character's maximum damage counter breaker combos on the individual character pages, so make sure you are not leaving any free damage on the table. Since heavy auto-doubles do the most damage per second in the game, the combo will likely consist of as many heavy doubles as you can fit in the 4 second window with as little filler as possible between them. Many characters will simply do heavy auto-doubles followed by light linkers for as long as possible, and then perform a damage ender. Some characters may be able to do slightly better than this by utilizing their combo trait (for example, Jago can use around the world to keep damage high while also increasing his instinct gauge), and you can always increase the damage if you’re willing to spend some shadow meter. If your character has a very fast shadow linker (like Glacius’ shadow Cold Shoulder), you can use two shadow linkers after a series of heavy auto-doubles to push the damage as high as 70%.
What should you do if your opponent tried to counter break and you didn’t fall for it? You need to make it hurt. If possible, try to avoid doing low-damage punishes, like a throw. Not only will your opponent get off the hook by taking a big risk without being punished for much damage, but throws are also performed with LP+LK, which the game might interpret as a break attempt if you enter it too quickly, which could trigger the counter breaker accidentally. Instead, you should start your punish combo with a high-damaging heavy normal and cancel it into a high-damaging opener (shadow openers work best, if you can spare the meter), then perform a combo as usual. Your opponent will be able to break this combo after the opener if he chooses to take the risk and predicts correctly, but you can also counter break or deliver very high damage if he locks out.
The mind game of when and when not to counter break is very unique to Killer Instinct, and it’s almost like a test of footsies during a combo. You can test your opponent’s reactions and his willingness to commit to high-risk, low-reward options, and vary your combo for a standard lockout or take a hard read for even more reward. You can notice patterns in your opponent, and perform baits of many varieties. For more discussion on this, see the Combo Breaking Strategy section.