Fear Multi-Takedown

The Fear Multi-Takedown (known as Double Fear Takedown when done on two enemies alone) is a new Takedown style in Batman: Arkham Knight. It replaced the Double Takedown in Batman: Arkham City and Batman: Arkham Origins for all playable characters in those games.

About
The attack allows Batman (and certain other characters, see below) to take down up to 6 enemies in rapid succession. It's activated by pressing Square/X/PC when near a group of enemies, and can also be activated by performing a knockout smash during any takedown. If the character is capable of FMT, using a double takedown will consume a charge.

Using the move creates a lot of noise and attracts attention, so stealth-wise, using the move isn't recommended unless the player can take down all the surrounding armed thugs at once or has an escape route planned out. Additionally, the move is very useful before entering combat, as it can be used either to thin the enemy ranks or to take down the most dangerous enemy types to make the fight easier.

Due to its power in clearing a large number of enemies, the player needs to perform any silent takedown to "charge" the attack after each time the move is used. Performing a knockout smash will not restore a charge. This limitation is only present in predator situations, and the move can be used more often in combat situations.

The move can also be interrupted by performing an "escape" move, which causes the character to quickly retreat either underground or to a vantage point, depending on which option was chosen.

The Double Fear Takedown replaced the Double Takedown from previous games, which resulted in Catwoman losing that move due to the male-centric nature of the Fear Takedown, and the male characters having to recharge the "Fear meter" in order to do this "new version" of the Double Takedown. Batgirl and Red Hood, however, can do a Double Takedown (and having quips to say mid-game after doing so) even though they can't do Fear Takedowns.

The Arkham Knight Incident
Batman used the move for the first time after upgrading to Batsuit 8.03, which allowed him more mobility. He rescued a hostage by quickly taking out the three guards watching over him. Throughout the night, Batman used the move whenever the situation called for it, and during certain Riddler Challenges.

A Flip of a Coin Incident
Robin, now capable of moving much faster than before, used the move to bypass two thugs and their sentry guns.

Waynetech
If you manage to initiate a Double Fear Takedown right at the start of a Fear Multi-Takedown, it's possible to take down one enemy more than these limits. That is to say, a Fear Multi-Takedown initiated with a Double Fear Takedown will incapacitate up to 6 enemies.

In a combat situation, each takedown adds 1 combat multiplier (the Double Fear Takedown immediately adds 2). If you successfully perform 5 takedowns with a Special Combo Boost upgrade, your combo meter will be full and you can use Special Combo moves.

Other Characters Capable of FMT

 * All male characters except Red Hood, including Robin, Nightwing and Azrael, can perform this move, but of course only in their respective DLC pack and challenge maps.
 * Batgirl can perform a Takedown very similar to this from above on panicking thugs (which has to be set up first), even though it is not labeled as "Fear Multi-Takedown", the enemies do not glow as an indicator in the process, and there is no "Fear meter", although the animations for this Takedown look more like those of Batman when he does his in a smoky area on confused enemies.
 * Batgirl and Red Hood can also do a Double Takedown without the need of a "Fear meter", and they also have quips to say mid-game after doing so.

Tips

 * Using a Smoke Bomb followed by a Fear Multi-Takedown to enter a fight can be used to make almost any combat situation much easier, although if any enemy sees the character entering the smoke, the move can not be performed.
 * Using a double takedown to start the attack allows performing up to 6 takedowns when the move is fully upgraded.
 * In "New Game +" (knightmare difficulty), if you have been spotted by a guard in Predator Mode and the guard is going to shoot you (this can be noticed when the time stops for a moment while the camera is aiming at the soldier that is going to shoot) while having a charge, the charge will be lost. You will have to perform another silent takedown to restore the charge, so in case you see that is difficult to take an enemy without alerting another one, it is advisable to use the smoke bomb to help taking a soldier out to restore a charge without taking the risk of losing it again (if you are lucky and the enemies are still stunned by the bomb you can actually perfom a multi fear takedown just after restoring the charge, although the smoke bomb does not tend to last that long unless with the longer duration upgrade).
 * This can be explained by the amount of adrenaline a person get when it manage to attack a predator that was hunting them down, the adrenaline reduces (or eliminate in really desperate cases) the fear on that person, and knowing that the predator can be hurt reduces fear on the rest of the soldiers as well.

Trivia

 * Moves that can be used to recharge the attack:
 * Silent Takedown
 * Corner Takedown
 * Ledge Takedown
 * Reverse Ledge Takedown
 * Vent Takedown