WARNING: The following article contains significant spoilers for Avengers: Endgame, in theaters now.

Audiences leave screenings of Avengers: Endgame with countless questions about the events of the film, and what they may mean to the future of the Marvel Cinematic Universe. Among those, no doubt for some, is, the identity of that tall, blond teenager at Tony Stark's funeral.

Virtually every living hero in the MCU pays their respects to the fallen Iron Man, with each character grouped with a "family": Aunt May appears next to Peter Parker, Scott Lang stands with his Ant-Man crew and so forth. Behind the "Secret Avengers" comprised of Scarlet Witch, Falcon and Bucky, however, there's a lone, lanky teenager standing on his own

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The only other characters standing on their own are Nick Fury and Maria Hill, so surely this one teenager must be significant, right?

Yes and no. That seemingly random teenager is actually Harley Keener, played by Ty Simpkins, last seen in 2013 as precocious, potato gun-wielding moppet in Iron Man 3.

Ty Simpkins as Harley Keener in Iron Man 3

Speaking of not seeing someone in over six years, that's coincidentally the same length of time that Harley had last seen his father in Iron Man 3. Seeing a bit of himself in this brilliant, fatherless wunderkind, Tony briefly takes Harley under his wing.

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At one point, by his own admission, Harley plays off of this abandonment angle in an attempt to guilt Tony into staying with him: "So now you're just gonna leave me here? Like my dad?" Tony does leave in order to save the world, but he doesn't forget about Harley, giving him a barn filled with tech goodies at the end of the film.

Ty Simpkins as Harley Keener in Iron Man 3
Ty Simpkins as Harley Keener in Iron Man 3

So, to recap Avengers: Endgame, Tony Stark initially chose not to help his fellow Avengers with their time-travel caper because he'd been father to adorable Morgan Stark over the past five years. He ultimately decides to help, however, primarily because he failed as a father figure to Peter Parker.

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Essentially, Tony's classic heroic dilemma in Endgame stems from serving as a father figure. He's forced to choose between the biological daughter he has and the metaphorical son he failed. On the sidelines remains Harley, whom Tony effectively forgot.

Directed by Joe and Anthony Russo, Avengers: Endgame stars Robert Downey Jr. as Iron Man, Chris Evans as Captain America, Mark Ruffalo as Bruce Banner, Chris Hemsworth as Thor, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Brie Larson as Captain Marvel, Paul Rudd as Ant-Man, Don Cheadle as War Machine, Karen Gillan as Nebula, Danai Gurira as Okoye and Bradley Cooper as Rocket, with Gwyneth Paltrow Pepper Potts, Jon Favreau as Happy Hogan, Benedict Wong as Wong, Tessa Thompson as Valkyrie and Josh Brolin as Thanos.