Oliver finally learns the identity of the man who's been trying to destroy him all season.
- Aesop Amnesia: Once again, Felicity doesn't remember that Keeping Secrets Sucks in regards to her having joined Helix.
- The Bad Guy Wins: There's a reason this episode is called Checkmate. By the end of the episode Adrian and Talia are able to capture Oliver and have him chained up in a Torture Cellar. Meanwhile the Green Arrow now has a shoot on sight order leveled against him and the rest of Team Arrow can't expose Adrian as Prometheus under threat of Oliver's death.
- Batman Gambit: Every move that Oliver and co attempt on Adrian he counters and uses said move to further his own plans. Invade Adrian's house to talk to his wife? Have the cops arrive and attempt to arrest the Green Arrow forcing Oliver to publicly call for a shoot on sight order. Give information to Da Chief about Adrian using a fake identity in order to have him kicked out of office? Stab said chief and leave him in a coma so Oliver loses an important ally and prevents the information from being leaked. The hostage you revealed your identity to escaped and is willing to tell the cops? Kidnap Oliver to ensure that both Susan and Team Arrow won't reveal your true identity.
- Big Bad Duumvirate: Chase is revealed to be working with Talia Al Ghul.
- Bring It: A silent variation: right before they fight, Oliver drops his bow to challenge Adrian to a more close-up and personal fight. Adrian responds by dropping his sword, and after that they start brawling all over the place.
- Call-Back: The Final Battle of Season 3 is integral to The Reveal of the episode.
- Call-Forward: Three times during the flashbacks.
- Anatoly rightly predicts that Talia will cause Oliver great pain in the future (without even directly knowing her, that is).
- Ishmael Gregor tells Oliver that if he kills him, he will only kill himself, which is uttered word for word by Adrian five years later. Interestingly, the scene plays after Adrian's scene.
- When going through Gregor's laptop, Anatoly and Oliver talk out loud about someone who could pull data off of a bullet-ridden laptop. A year later, Oliver will find someone who is able to do so.
- Cold-Blooded Torture: Adrian puts Susan through it. When Oliver finally rescues her, she is bruised, with cuts and dried blood on her face.
- Combat Breakdown: The fight between Oliver and Adrian/Prometheus is different from their previous encounters, having significantly less finesse to emphasize how much they've come to hate each other. While previous clashes have involved weaponry and remarkable skill from both men, here they immediately drop their weapons and try to rip each other to shreds with their bare hands.
- Combat Pragmatist: Talia shows up in the final minutes of Prometheus and Green Arrow's battle and puts an arrow into the latter's left leg while his back turned.
- Curb-Stomp Battle: Anatoly and Oliver absolutely destroy Gregor and his men during the attack on the ice rink.
- Deal with the Devil: Felicity quickly realizes she's over her head when Helix starts asking for a "quid pro quo" arrangement for their help, such as asking for things like hacking into government drones.
- Diabolus ex Machina: At the end, Oliver seemingly finally defeats Adrian in a fight... and then Talia arrives and incapacitates Oliver when his back is turned.
- Digging Himself Deeper: Thanks to Adrian's manipulations every move that Oliver makes forces him to throw his Green Arrow alter ego under the bus and, by the end of the episode, the Green Arrow now has a shoot on sight order leveled against him.
- Divide and Conquer: Adrian makes sure to lay heat charges throughout the abandoned building he's holding Susan in so that Team Arrow will be forced to split up and, with a couple of timed charges, manages to level parts of the building to separate Oliver from his team. The end result of this is that Oliver ends up captured by Adrian and Talia by the end of the episode.
- Even Evil Has Loved Ones:
- Talia admits that although she and her dad had a falling out, she still loved him — this is in a direct contrast to Nyssa, who came to hate her father after their falling out. Then again, (as far as we know) Ra's didn't try to kill her and then forcibly marry her off like he did with Nyssa.
- Adrian obviously cared about his wife, but not enough to not kill her to keep his secret.
- Evil Gloating: Chase spends basically the entire episode rubbing his superiority under Oliver's nose. The only time he loses his composure is when Oliver brings in his wife, and even that doesn't completely faze him.
- Face–Heel Turn: Talia was more or less an Anti-Hero in the flashbacks, training Oliver to become The Hood, himself a Byronic Hero. In the present day she's a full-blown villain, as she wants revenge for Oliver killing her father.
- Foreshadowing: Early in the episode, Curtis tells Oliver that the name of Talia's monastery translates as "demon something".
- Genre Savvy: Mr. Terrific tells Canary not to explore the serial killer's mom's creepy house, because it never works out in the movies.
- The Gloves Come Off: At the beginning of their fight this episode, there's a moment where Oliver and Adrian just stare at each other. Then Oliver drops his bow, followed by Adrian dropping his sword, and the fight that follows is little more than a straight-up brawl. This moment really emphasizes how much they've come to hate each other, in that they don't care about anything else other than hurting each other as much as possible.
- Greater-Scope Villain: Talia has been the true villain of Season Five all along, having trained Prometheus for the sole purpose of getting revenge on Oliver.
- Ignored Epiphany:
- Even though he seems shaken by his wife's appearance and having to kill her, Adrian is back to his smug, sadistic persona merely moments after it.
- Felicity ignores any doubts she has on working with Helix, when Prometheus kidnaps Oliver since she's so desperate to find him.
- I Have Your Wife: Done by Adrian with Susan, later attempted by Oliver and John with Adrian's wife, but it doesn't play out the way they hoped it would.
- Internal Reveal:
- Oliver learns both the identity of Prometheus and that Talia is the other daughter of Ra's.
- Prometheus reveals how much he knows about Oliver when he name drops Shado, whom no one outside of Sara, Slade, and Shado's twin sister should know about.
- Jumping Off the Slippery Slope: It's clear Adrian does seem to love his wife, but when she discovers the truth about him he breaks down in tears and murders her, effectively severing his last remaining link to any remote semblance of humanity, now fully dedicating 100% of his life to destroying Oliver.
- Keeping Secrets Sucks: Oliver lampshades this in his conversation with Felicity, seeming to have finally learned it after five years.
- Kick the Dog: Adrian never stops throughout the entire episode.
- Kick the Morality Pet: Adrian murders his wife to keep his identity a secret, even though he is clearly distraught about it.
- Killed Off for Real: Ishmael Gregor is apparently killed during the flashbacks, alongside all of his men.
- No-Holds-Barred Beatdown: During their fight, both Adrian and Oliver drop their weapons and give each other an absolutely brutal beatdown with their bare hands.
- No-Nonsense Nemesis: Adrian wasn't showing off by saying that he is always 10 steps ahead of Oliver. The only thing he didn't plan for was his wife finding out the truth, but even this doesn't set back his plans.
- Oh, Crap!: Oliver when Talia reveals her last name: Al-Ghul.
- O.O.C. Is Serious Business: It's subtle, but the only time Adrian loses his composure is when his wife finds out his secret and he is forced to kill her to keep it. Right before the fight that immediately follows, one can see a brief look of rage on his face when he drops his sword to go at it with Oliver the old-fashioned way.
- The Reveal: Talia has been backing and training Prometheus to get revenge on Oliver, although she notes that Prometheus sought her out on his own and had already learned much about Oliver.
- Revenge Myopia: Both Talia and Prometheus want revenge on Oliver for killing their fathers — not caring that they were horrible people who killed scores of innocent people. Prometheus could at least make the argument that his father was killed in cold blood, while Ra's was more than capable of defending himself and was about to destroy an entire city just to ensure Oliver would become his heir.
- Shout-Out:
- Simon Morrison, Adrian Chase's/Prometheus' real name, is likely one to Grant Morrison, creator of the comics version of Prometheus.
- Although Adrian seems to truly love his wife, he still murders her upon her finding out the truth in order to dedicate his life full-time to vengeance. This calls to mind the character of Iago.
- Smug Smiler: Adrian, combined with Evil Gloating listed above.
- Start My Own: Talia's monastery is her own version of Nanda Parbat.
- Tantrum Throwing: After being taunted one too many times by Adrian after the latter put Captain Pike into a coma, Oliver starts destroying equipment and inventory in the Arrowcave.
- Villainous Breakdown: The one and only time throughout the episode Chase's smug facade starts to crack is when his wife appears at his base alongside John and Oliver.
- What the Hell, Hero?:
- Felicity expects to get this from Oliver for being awol from her Team Arrow duties. Instead, Oliver tells her that he's worried about her since he knows she's keeping something shady from him — Keeping Secrets Sucks after all, but he won't press her from details.
- Curtis scolds Felicity when he realizes he is helping her hack Homeland Security and she refuses to tell him what this is all about.
- Wham Line: From Oliver's perspective (but the audience is already in the know).Talia: I helped him in his pursuit of vengeance because by then, you'd killed mine. I never told you my full name, did I? ... It's Talia al Ghul.
- Worthy Opponent: Oliver seems to regard Ra's as this. Ra's had honor — something his eldest daughter lacks.
- Your Princess Is in Another Castle!: Dinah and Curtis explore Chase's mother's house when they hear a scream from upstairs. When they break into the room, they find Prometheus holding a knife at Susan's throat, on a television screen, on a loop.
- You Killed My Father: Talia's justification for betraying Oliver — he killed her father.
