Foreshadowing / Batman: Arkham Knight

• The game starts with Joker's cremation set to the tune of Frank Sinatra's "I've Got You Under My Skin". Later in the game, we find out Batman still has some traces of Joker's toxin in his blood which activates when hit by Scarecrow's new fear toxin. Causing Batman to see hallucinations of Joker which indeed threatens to take over Batman's personality.
• The very first thing we see in the game is the label on Joker's cremation chamber - "ROBINSON". Or "ROBIN SON", if you read it with a space in there. A major theme of the game is that Batman sees his sidekicks as family. The game's main villain is ex-Robin Jason Todd lashing out at his old mentor and adopted father for replacing him.
• The character list gives two characters identical vital statistics, namely the Arkham Knight and Jason Todd. This is another hint to the Knight's identity.
• The smoker in Pauli's Diner is wearing a hood, so the player can't see them before Scarecrow's fear toxin kicks in and everyone in the diner suddenly looks like a zombie. The smoker was wearing a red hood, hinting that he was the Batman character Red Hood, who we later learn is working with Scarecrow as the Arkham Knight.
• Relating to the disappearance of Henry Adams:
  • There's a flyer on the refrigerator at Pauli's Diner stating that a local man named Henry Adams has gone missing. Sure enough, it's revealed later that he's been abducted — by Batman himself; as the only transfusion recipient with natural immunity^note Seemingly, at least to Joker's blood, he was instrumental in Batman and Robin's attempts to synthesize a cure.
  • Out of all the Jokerized citizens, Henry is the one whose physical appearance most closely resembles the real Joker, to the point that it looks like he could almost be an older relative, only without the skin or hair coloration. Turns out to be a hint that he's the most Joker-like of all of them, and not immune after all.
  • A hint that Henry isn't quite as immune as originally believed (and the one who hacked the security system) shows up when Batman asks him to help with hacking a security camera. He makes sure to tell Batman that he doesn't really know anything about computers to throw him off, before proceeding to do as Batman asked much faster than anyone who's genuinely computer-illiterate could be expected to. He does state that the interface is much simpler than a normal computer layout, though in hindsight, this appears to be a taunt of sorts.
• Similarly, billboards for the cocktail singer Johnny Charisma's live Halloween show appear throughout the city. While some fans' initial interpretations of a hidden message^note "JO C AR IS A LIVE" seemed outlandish, it's later revealed to be somewhat true; Johnny, another infected blood recipient, is slowly becoming more Joker-like in his appearance, complete with a similar hairstyle and an equally ostentatious lounge-lizard suit. Batman even later hallucinates variations of the billboard where Joker's the one hosting the show.
• When Gordon meets Batman in the holding area for the Joker Infected, he counts only four people, though Batman said there were five. A hint comes immediately after of who the fifth Infected is: Batman steps close to the empty fifth cell, and his own reflection appears in the glass, and he says, "He'll be here soon."
• There's a hint in Barbara's "death" that the scene is a fakeout - the Joker hallucination visibly moves her gun before she picks it up. Joker also gets directly in front of Batman when she actually shoots herself; while it plays like a Gory Discretion Shot in the moment, it's also a hint that she never actually shot herself.
• Joker's first lines after he reveals himself to Batman in the ACE Chemicals building, "We're going to give Gotham the Batman it deserves. A new Batman. A better Batman. A darker, more- well, we can come back to this later." As seen in the Golden Ending, Gotham got just that.
• When the Knight shows up in his chopper, he targets Batman and says "Time to die, old man." Another meaning of the term 'old man'? Father. Appropriate for Jason, who feels betrayed by his father figure.
• After unmasking the Arkham Knight, Joker's hallucination waxes nostalgic about the asylum the Knight named himself after and says "maybe we'll get to go back there someday!" Scarecrow brings Batman back to Arkham Asylum for the final act.
• The first line of the Joker's song, "take me on home to the Asylum", foreshadows Batman's return to Arkham Asylum, where Joker takes full control before being banished into the deepest parts of Batman's mind.
• At the beginning of the 'Friend in Need' sidequest, when Bruce Wayne is entering Wayne Tower, there's a hint that it isn't really Bruce Wayne: before, when listening to Bruce's voicemail, there are mocking messages from the Joker fragment, which obviously are only happening in his head; when 'Bruce Wayne' checks the messages, he only hears the four from real people.
• The Joker/Jason Todd hallucinations make it painfully obvious who the Arkham Knight is.
• After Scarecrow gasses Batman on Stagg's airship, he asks Batman what he can see: "the city engulfed in fear? Betrayed by those you trust the most? Your darkest secrets revealed?" It sounds like typical villainous bluster, but he manages to make it all happen by the end of the game - the Cloudburst briefly drowns Gotham in fear gas, Gordon shoots Batman on Scarecrow's orders, and the world learns Batman is Bruce Wayne.
• When Batman heads to surrender to Scarecrow near the end of the story, check the wall outside and you'll see a spray-painted red Batsymbol. It's also the Red Hood's symbol, letting the player know he's following Batman before Hood rescues him from Scarecrow.
• The newspapers lying around in the Clock Tower headlined with "BATGIRL SAVES COMMISSIONER" seem to be foreshadowing the "A Matter of Family" DLC, where Barbara does exactly that.
• When you reach the penultimate weapons cache in Penguin's side-quest, Nightwing is noticeably absent. Because he had gone off to find the last cache and got himself captured by Penguin.
• Near the end of the first segment of the weapons cache side-quest (which is completed as part of the main story), as Batman is closing the vault door to protect himself from the explosion the hallucination of Joker pretends that Batman is locking him up inside the vault, jokingly begging and pleading not to be locked in. This ends up hinting at his fate in the game when Batman purges the Joker from his mind by locking him up in a cell to be trapped in the darkest corner of his mind for eternity, with the Joker hallucination similarly pleading not to be trapped inside, only this time he's no longer kidding around.
• During Batman's first face-to-face encounter with the Arkham Knight, the other soldiers are told to not shoot the bat symbol on his armour because that's where the armour is thickest. When Batman uses the remote control on the Batmobile to surprise the mercs, Knight immediately grapples out, much like Batman himself would. Or someone he trained. Much later, Gordon shoots Batman there intentionally, "killing" him and knocking him off the building in order to escape Scarecrow's machinations.
• After Batman tells Jim that Barbara was captured, they head to the clock tower, only to get attacked by the Knight's militia jeeps. The Arkham Knight demands Jim to be brought to him alive. This is because they were planning to blackmail him to join their side; Batman is led to believe Barbara died, while Jim is still captured and likely knows the truth.
• When Batman contacts Lucius to instruct him to open the Wayne Tower Parking Garage, Lucius comments with mild confusion that he believed Bruce was already in the building, hinting that Hush had already entered the building.
• Some of the chatter in the Militia watchtowers makes reference to things not revealed to the player until later; on the watchtower overlooking the most southernly bridge connecting Founders Island and Miagani Island you can hear the militia soldiers speaking about an assassin brought in by the Knight as an advisor, referring to Deathstroke who takes command after the final fight between Batman and the Knight while the militia soldiers in the Watchtower situated on a walkway between two towers, next to a bridge to the mainland and just north of Wayne Tower, mention that they plan to retrieve their captive brethren from the GCPD, claiming that the "Cops will never see it coming." Hinting at the siege of the GCPD, which serves as the action climax to the main story, before the confrontation in Arkham Asylum finishes the story proper.
• Several of the stories unlocked through riddles foreshadow elements of the Season of Infamy missions including Nora being consious inside the ice, Mad Hatter forcing a man into being Alice, and the schism within the League.
• When the Arkham Knight appears in full for the first time, he points out to his militia soldiers that the bat symbol on Batman's chest is a decoy encouraging them to shoot there when, in fact, it's the strongest part of his body armor, and this is reiterated once or twice later in the plot as well outside of cutscenes. Almost at the end of the game, Batman is put into a standoff with Scarecrow and Commissioner Gordon with another life on the line, forcing the other party to shoot him in the chest and seemingly kill him, only for the hostage to be thrown off the top of the building this is taking place on. Batman swoops in almost at the last moment to save the hostage, who is amazed that he's alive, but Batman points to the where the bullet hit: right on the bat symbol. "He knew what he was doing."
• It's hinted from about halfway through the main plot that the Arkham Knight's true identity is Jason Todd, the second Robin. Batman sees a Remember the New Guy? vision of his seeming death, as part of a series of all the terrible things The Joker did in the past. Savvy players will realize the scene's real purpose is to make The Reveal not come out of nowhere.
• Another hint to the Arkham Knight's true identity can be found in the character bios. Jason Todd and the Arkham Knight are listed as having the exact same height and weight.
• Late into the game the Militia side quests (Campaign for Disarmament, Own the Roads and Occupy Gotham) are revealed to end with a grand finale battle with Deathstroke. Fans paying attention to the Most Wanted page will likely be able to predict that this fight would turn out to be another stealth Tank Battle, like the Cloudburst tank battle from earlier in the Campaign by noticing which mission is marked to have a final mission; Campaign for Disarmemnt, which is focused on Tank combat.
• If you visit the evidence room after Joker starts appearing as an hallucination, he'll lament that his equipment is sitting there with no one causing mayhem with them and that he didn't get so much as a statue to his name, he says that he shouldn't be forgotten like this. in the ending it's revealed that it's his greatest fear, which Batman uses to finally get rid of him for good.

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