Below, you'll find location data for all 16 firefighters who will need the Caped Crusader's help before the end of the game, along with some tips on how you might go about locating/rescuing the firefighter in question. We also welcome input from the Batman: Arkham Knight community, especially if you've come up with a successful strategy not listed in my guide.
So, without further adieu, here's where you can find all 16 firefighters from Batman: Arkham Knight's Line of Duty side quest.
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Line of Duty Firefighters - Bleake Island
Firefighter Adamson
Location: Chinatown
You'll find Adamson being held captive northeast of the bridge to ACE Chemicals. You'll only have to deal with a few unarmed thugs to free him but keep an eye out for rioters who might join the fight.
Firefighter Ashley
Location: Chinatown
Like Adamson, Firefighter Ashley is being kept in Chinatown under the watchful eye of knife-wielding thugs. Once again, keep an eye out for Rioters. They seem to be quite a bit more common in Chinatown than other parts of the map.
Firefighter Cannon
Location: Chinatown
For some reason, Chinatown seems to be a popular destination for the various groups of thugs who've been kidnapping GCFD members. Like many of his fellow firefighters, Cannon is being guarded by armed thugs (equipped with stun batons) but those who manage to track Cannon down (across from the Clock Tower) shouldn't have much trouble with the local criminals.
Firefighter Norman
Location: Chinatown
Time for another trip to Falcone Shipping. Firefighter Norman can be found on the northeastern edge of the company's property, along with a handful of guards, but careful players shouldn't have any issues rescuing Norman from his captors.
Firefighter Wood
Location: Dixon Dock
Rescuing Firefighter Wood is pretty straightforward. Head down to Dixon Dock West, locate the security office and take care of the handful of guards keeping an eye on the fireman. Don't start getting cocky, though. They won't all be this easy.
Firefighter Wyatt
Location: The Cauldron
Wyatt might be one of the easiest firefighters to locate, primarily because he's being held near the cranes positioned outside of Falcone Shipping. This marks the first time you'll encounter a firefighter with armed guards but it won't be the last.
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Line of Duty Firefighters - Founders' Island
Firefighter Bliss
Location: Wayne International Plaza
Firefighter Bliss & Co. should be pretty easy to spot from the top of Wayne International. The group is situated on the north side of the plaza, with two brutes to keep things interesting, and we'd recommend trying to get close enough for a Fear takedown on the unarmed guards. That way there shouldn't be anything stopping the player from giving the Brutes his/her undivided attention.
Firefighter Lozar
Location: Ryker Heights
You'll need the Batmobile (briefly) to free Firefighter Lozar from his captors. Drive over to Ryker Heights and use the vehicle's winch to create an opening in the northwest edge of the building where Lozar is being held captive. Once inside, do what you can to remain unseen while dispatching the armed guards keeping an eye on Lozar and you'll be on to the next one before you know it.
Firefighter Scott
Location: Ryker Heights
Thugs have taken Firefighter Scott over to a pier in the northern section of Ryker Heights. Once you've tracked down the right spot, hold off on attacking the guards gathered around Scott until after you've dealt with the sniper providing cover fire from the nearby lighthouse.
Firefighter Taylor
Location: Port Adams
Firefighter Taylor is being held prisoner in the control room at Port Adams, which can be found in the center of the facility. You'll definitely want to take the stealthy approach for this one, eliminating guards one-by-one until the only people still conscious are Batman and Taylor.
Firefighter Wilson
Location: Ryker Heights
Wilson is being held at the Urbarail Station in Ryker Heights, giving the dozen-plus guards assigned to keep an eye on the firefighter plenty of cover to ambush the Dark Knight from. Players are advised to use a combination of silent and Fear takedowns to eliminate the standard guards. And you'll probably want to keep the Brutes separated, otherwise there's a good chance Batman: Arkham Knight's oversized enemies will overwhelm the Caped Crusader.
Fire Chief Underhill
Location: Ryker Heights
Chief Underhill is being held captive at the City Vision Building. Like any multi-enemy encounter, your best bet is going to be heading to the top of the building, using Detective Vision to identify all nearby enemies and then taking your time to work through all 16 of Underhill's guards.
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Line Of Duty Firefighters - Miagani Island
Firefighter Green
Location: Mercy Bridge
There's a good chance you'll stumble across Firefighter Green by mistake. Or maybe we're just bad at running across the steel beams holding Mercy Bridge together. Green can be found at water level, surrounded by gun-toting guards that you'll need to deal with pretty quickly. We recommend making sure you're Fear meter is full before taking a shot at the Green rescue.
Firefighter Hill
Location: Kingston
Strangely, Firefighter Hill doesn't have much in the way of protection. Hill can be found in Kingston, near the Gotham Herald Building, and provides a brief respite from the gun-toting criminals guarding many of the firefighters for the Line of Duty quest.
Firefighter Richardson
Location: Kingston
You're going to want to recover the Remote Hacking Device before attempting to rescue Firefighter Richardson, thanks to the six sentry guns and handful of armed guards waiting for the Caped Crusader to make his rescue attempt. With proper preparation, Richardson isn't particularly difficult to rescue. But those who rush in blindly probably aren't going to have much success.
Firefighter Daniell
Location: Wayne Tower
We're not sure what Firefighter Daniell did to deserve so much unwanted attention, since he's being guarded by close to a dozen armed guards, but the Dark Knight's work is certainly cut out for him this time. We recommend using the Disruptor to neutralize as many firearms as you can, depending on the talents you've chosen, and then using your Fear takedown to quickly remove 3-4 enemies. From there it's just a matter of quick reflexes, and proper smoke pellet usage, to rescue Daniell.