And in the same vein, is Peter Wisdom a.k.a. Regulus Black much the same in terms of being dedicated to protecting humanity from the monsters in the dark, or is he a half-crazed power hungry Manipulative Bastard and an obsessive Hunter of His Own Kind dedicated to forcibly taking control of the Wizarding World and bringing it to heel? Judging by chapter 72, a little from column A, a little from column B. He sees bringing the Wizarding World to heel as the primary means by which he can protect ordinary humanity.
Is Sean Cassidy really a fairly happy go lucky fellow, determined to be cheerful despite it all, or is that simply amask for a cold, Revenge obsessed master spy and assassin?
Is Harry a remarkably well-adjusted, mature, if snarky kid (considering the Avengers, the latter is inevitable), with the potential to be his generation's Captain America? Or is he a Shell-Shocked Veteran whose snark is a defence mechanism, a de factoChild Soldier with a Hair-Trigger Temper used to using intimidation to get his way, who is slowly developing into a Dark Messiah on par with or beyond Magneto himself? The answer, as Doctor Strange remarks in chapter 75, is that he could quite easily become either depending on the choices he makes. One way he could become a great hero, the other way he could become 'the thing men fear'.
Is Doctor Strange a benevolent Deadpan Snarker and Big Good for the universe who works tirelessly to ensure that the good guys get through largely unscathed and deeply regrets the sacrifices he must make, or is he a spectacularly ruthless Manipulative Bastard running a Xanatos Gambit of unimaginable scale, whose benevolentfaçade falls away when it is not needed, trades on his cultivated reputation for never lying to ensure that people do what he needs them to, turns children and adults alike into his weapons in ways so subtle that they don't even notice and is entirely willing to sacrifice thousands of good people through action or inaction in order to sharpen his tools for a future battle and bring about his vision of a better future?
Chapter 80 reveals it is both. While, yes, he could have just saved the day by revealing everything he knew, it would have resulted in potentially worse results, and none of the friendships and good ties made due to the fight against HYDRA would have happened. He regrets that so many people died, and wishes he could have done otherwise, but had he prevented the deaths of today he would have been unable to stop the disasters of the future.
Crosses the Line Twice: In Chapter 17, Thor proclaims (on Harry spending an instructive half an hour with Tony and Darcy) that Lily will probably return from beyond the grave to strangle him for this. Cue Loki conjuring an illusion of an infuriated Lily. Thankfully, Thor takes it pretty well.
Crossover Ship: It's revealed that McGonagall was the fiancee of Bucky Barnes. It becomes more meaningful when it's revealed that she was pregnant when he "died," and reveals that Hawkeye is her grandson. Meaning that Clint is the grandson of one of the most powerful witches alive and the Winter Soldier, the world's most notorious assassin.
We've also seen the early stages of Lex Luthor/Susan Storm.
Previously, there's been Wanda Maximoff/John Constantine.
In chapter 37, Tony notes that Loki 'has thirty six fansites, seven of which are solely dedicated to working out what he'd look like in tight leather pants'.
Ensemble Darkhorse: Has quite a lot of these thanks to the author's penchant for reimagining characters, as well as throwing in those characters at the last minute, later developing them into prominent figures in the story. The two main examples come in the form of Carol Danvers and Diana of Themyscira, both of which were added in at the last minute, apparently entirely on a whim and praised as original takes on the character. They've both grown from fairly minor characters into two of Harry's closest friends, two of the more Badass characters in the story and bona fide fan favourites - in a poll of favourite new or reimagined characters, Diana was the runaway winner, with Carol being joint third behind (unsurprisingly) the Winter Soldier, who's even more of a Woobie than usual thanks to the sections from his perspective, and sharing third place with Huginn and Muninn. Indeed, Carol's grown into a full on Breakout Character, being close to a Deuteragonist with Harry, and she and Harry are now the Fan-Preferred Couple (with Harry/Diana being close behind).
On the villainous side of things, Gravemoss started out as a minor, creepy Necromancer who was the villain of a minor arc in Excalibur and included simply for variety. He quickly grows into a major league villain and a character that fans love to hate.
Then you have Lucius Malfoy who is the epitome of From Nobody to Nightmare. He started out as just an underling for Lord Voldemort but gradually grew into not just a magnificent bastard but into a more formidable opponent for The Avengers. He even succeeds in taking over the world, even if it was temporarly. While doing it with such style and sophistication.
Sean Cassidy is added for the sake of variety to Peter Wisdom's Exalibur squad, but despite initial uncertainty by fans, grows into a popular mentor figure to Harry, something helped by his nature as an Adaptational BadassGrandpa, something helped by the way he gently reins Harry in when he looks to be going too far and the bond he has with Luna Lovegood.
Fan-Preferred Couple: while neither of these pairings has come about, fans have vocally called for Harry Potter/Carol Danvers, on the grounds of the considerablechemistry the two share despite their mutual insistence that they are Just Friends, over the Word of God stated original plan of Harry/Ginny. While the author has been enigmatic about the former, the latter has been confirmed to have been removed, as part of a raft of grand scale changes to the future of the story.
The story also manifests an example of this trope, with a strong Bucky/Natasha dynamic woven in, despite the fact that the fic as a whole is heavily based on the Marvel Cinematic Universe, with not even a tiny bit of Bruce/Natasha chemistry (despite it being MCU canon).
Relatively early on, the author created a poll out of curiosity to see who fans would prefer Harry to be with. Jean Grey won by a clear margin, with Emma Frost and Hermione Granger not far behind, tied in second place. Based on Word of God, Harry's not going to be paired with any of them - Jean Grey is his cousin and Cool Big Sis, though a letter written by a version of Harry from the future notes that she's 'disconcertingly attractive' and pretty definitely shipped with Scott Summers, Emma Frost and Harry are stated not to get on at all and the narration has on more than one occasion noted that Harry very rarely notices that Hermione is female and is 'about as attracted to her as he is to mould'.
A more recent poll shows that Harry/Carol is now by far the most popular potential ship amongst the fanbase, with Harry/Diana being a relatively close second.
If you had any doubts about the identity of 'The Hidden World', as the author note mentions, translating 'The Hidden One' into Ancient Greek reveals the name of the planet. Krypton.
The title of Chapter 34 ("Fool's Gambit") is both a reference to the insanity of Harry's Crazy Enough to Work plan and the name of a chess strategy which relies on acting fast, Refuge in Audacity and taking the opponent offguard. Much like Harry's plan.
Growing the Beard: The fic really hit its stride right around when The Winter Soldier is introduced and starts wreaking havoc.
Chapter 16 is literally called "Magnificent Bastards," which is unsurprising considering it focuses on Lucius Malfoy and Loki.
Doctor Strange is basically Havelock Vetinari with magic powers and an insight into the future, perpetually being several steps ahead of everyone else and, more to the point, using them as pawns - something which proves to be Paranoia Fuel for Lucius in chapter 72. Chapter 75 gives an insight into the sheer scale of his operations.
Moral Event Horizon: Gravemoss goes shooting over it in chapter 21, enjoying himself immensely as he does.
One-Scene Wonder: Not strictly confined to one scene, but where the Winter Soldier is concerned, this applies.
Ron the Death Eater: Refreshingly not with the character himself, who actually comes off as the Only Sane Man when compared to the rest of the deeply eccentric cast.
Snape, however, is not so lucky. While not being outright despicable or villainous, and having his good deeds (namely, protecting Harry) acknowledged, the fic does make him come off as a petty individual who uses his past grudge against James to torment Harry. Sometimes the treatment goes into Butt Monkey territory.
Slow-Paced Beginning: One criticism is that the story starts slowly and takes a few chapters to find its stride.