- Tony slowly dying after his armor is forcefully removed by MODOK in the pilot. The look on Captain America's face as he's watching his best friend apparently die before his eyes really sells the scene.Tony Stark: Hey Cap, remember how far I went to pull your butt out of the fire? Your turn. *smirks weakly and passes out.*
- Tony's reaction at the beginning when Captain America is seemingly vaporized, as well as the more subdued but no less saddened reactions of the other Avengers when they find out.
- In Hyperion, the Avengers each fall one by one from the might of the catastrophically-sized meteor after it reaches Earth's atmosphere. With only Iron Man left to hold the giant space rock, he apologizes to his team saying it's just too much for the Avengers to handle, and that Earth is more than likely doomed. The music surprisingly fits for this rather bleak beginning of the episode.
- Near the end of Hulked Out Heroes, Hulk leads Black Widow to an undisclosed location to retrieve a pair of gloves that would turn the gamma-mutated Avengers back to normal. However, he warns Black Widow to not use it on him as a cure for his monstrous state, for it would turn him to ash. What really tugs the heart strings is Black Widow's very subtle worried reaction. For a moment, she loses her stoic personality knowing that if she misaims ever so slightly, it could kill the person who trusted her for so long, and one of the few people he considers a true friend.
- Tony's outbursts while trying to work on a cure seem funny, until you realize he's desperately trying to keep his wits long enough to save himself and his friends.
- Thor's reaction to his friends helpless or turned against him in the new timeline caused by Doctor Doom changing history to where he's ruler of the entire planet in Planet Doom.
- Thor completely loses it when he sees Captain America's frozen form sitting in Doom's chamber on display, as if he was some kind of trophy.
- As Thor is about to be executed by Doom, he makes one last plea to the people of the world. Only to be rebuffed coldly by a beaten and broke populace.
- Torgo's backstory. While simplistic, adds a little more weight to the character. Especially compared to his flat, villainous counterpart in the comics.
- After MODOK has hacked into JARVIS in Bring on the Bad Guys, the poor A.I. is not only forced to help the Cabal. Skull forces him to call him "master".
- Not only that, Skull never calls JARVIS by name, only ever calling him "computer".
- During Crime and Circuses, Clint's obvious shame in regards to his time as a criminal in the Circus of Crime gang.
- Iron Man sacrificing his freewill to join Galactus. Helped by the fact that it becomes a big enough problem to which the Guardians of the Galaxy have no choice but to kill him, despite the Avengers' pleas to stop.
- Tony's bout of depression during Exodus after watching Falcon get hurt, all because he made a tactical error.
- While Cosmic-Skull was vicious to all of the Avengers, what he did to Hawkeye seemed the most cruel.Hawkeye: (terrified) My eye's. I'm blind!]
- Doubles as a Heartwarming Moment from The Arsenal, Iron Man succeeds at finding his dad's long lost Project Arsenal; a robot capable of withstanding unlimited energy. The Tear Jerker comes in play when he discovers the android's main purpose was to make up for all the lost time that Tony's father never had with his son.
- The "death" of Arsenal in Thanos Rising, even the Watcher seemed saddened. It gets worse when you realize this parallels what happens to Baymax.
- Bucky's fate as revealed in Ghosts of the Past. He's basically become a monster, bent on destroying the Red Skull no matter what. The worst part? Steve blames himself for it.Bucky: You may have been my friend in the war, but now you're just someone standing in my way.
- Kid!Tony looking through a box of his old stuff and finding a picture of him and DUM-E alone on his birthday. There's also a birthday card from his father. The name "Howard" is crossed out, replaced by "Dad" like it was an afterthought.
- Tony pulling a Heroic Sacrifice to save the rest of the team from Nighthawks bomb in The Dark Avengers.
- Watching Thor giving up when he thinks he's failed the trial in Back to the Learning Hall.
- That and the stupid magical statue continually ponding his head into the ground as it bellows "failure" over and over.
- Arsenal returns in Thanos Triumphant, a very Heartwarming Moment. That is, until Ultron steps in and takes him over in both mind and body.
- The fracturing of the Avengers in Avengers Dissembled. It gets particularly heartbreaking with Thor and Hulk.
- Spider-Man scolding Tony for his bad leadership and Steve for not standing by the team.
- The ending of The Ultron Outbreak was just heartbreaking when Arsenal briefly overtakes Ultron, and sacrifices himself to destroy Ultron.
- Arsenal referring to Tony as "friend" before plunging himself to the sun.
- The way Tony cried out for Arsenal was just heartbreaking.
- Arsenal referring to Tony as "friend" before plunging himself to the sun.
- From Spectrums, the fact that the innocent Doctor Spectrum was forced by the rest of the Squadron Surpreme to blow up his home planet is staggeringly dark and tragic.
- He also makes Thor, Cap, and Iron Man (in that order) fight enormous illusions of a villain personal to them. While Tony just has to contend with Ultron taunting him, Cap and Thor are sent on guilt trips by Winter Soldier and Loki, respectively.
- During the opening of "Avengers Underground", when Red-Hulk (among several other heroes) is shown having been captured by the Squadron Supreme.
Saving Captain Rogers
- Steve is forced to relive one of his battles from 1940's Europe, to rescue Bucky who had been captured by Baron Heinrich Zemo. Of course what's really happening is that he'd been hypnotized by the episodes villain just so he can get his hands on the Baron's MacGuffin. Throughout the episode, Cap suspects something isn't right. But he's so desperate to save Bucky that he ignores his instincts. What makes it even sadder is that this was the very event that led to Bucky becoming the Winter Soldier.
Inhumans Among Us
- The young boy Dante having to come to terms with learning he's Inhuman, poor kid is pretty confused. Thankfully, he gets over it pretty quick.
Into the Future
- This episode makes it clear that no matter what happens, Thor will end up outliving his teammates, because he''s the only one who's immortal.
- While they fought, Steve never stopped trying to explain to Kang that he didn't have to be just another dictator. That if he didn't stop, he'd end up like all the other villains that came before him. Sadly Kang rejected all of Steve's attempts to reason with him.
The House of Zemo
- Steve, having lost his only photo of the man years ago, is having trouble remembering what his father looked like. To not be able to recall the face of the man who raised you (or any close family member) is a really heartbreaking thought.
- You can't help but feel a little sorry for Baron Zemo, who went to such lengths to honor his father's memory and even bring him to the present, only for that father to constantly deride him and consider him a disgrace to the family name.
- Hulk being kicked off the team by Truman Marsh, and forced to leave behind his closest friends. The fact that he resigns himself to it so quietly, without any trace of anger, just makes it all the more tragic.
Building the Perfect Weapon
- Seeing Hulk wander around, alone and friendless, without any purpose or direction. Anyone he encounters on his travels just recoils with fear at the sight of him. And to top it off, he's been fitted with an electric collar that electrocutes him whenever he tries to use his strength, meaning he can barely even help people any more.
- Part 1 begins with Dante suffering a bad case of Power Incontinence. This leads to him spontaneously causing mass fires by accident, which decimate all of Attilan. Though Hulk is eventually able to calm him down so he can regain control, the damage is already done.
- In the end, Dante and the rest of the Inhumans agree to comply with the Inhuman Registration Act.
- Near the end of Part 2, both Avenger teams' horror when they realize Captain America was very badly injured during their fight. Vision takes it pretty hard when he realizes it was his throwing Mjolnir that got Cap hurt.
- Part 4 has a Bittersweet Ending when The Avengers free Tony from Ultron's control but Ultron still lingers in his arc reactor. Strange decides the best thing to do would be to send Tony to a different dimension to both preserve his life and stop Ultron. The heartbreak is evident on the Avengers face as Tony says goodbye to his friends. Though he can still communicate with them, there's still the fact he's trapped there until they can find a way to free him from Ultron and keep him alive.
- Tony and Steve's goodbyes are particularly Tearjerking.
- In Ms. Marvel's short's ending, she's forced to admit that she isn't ready to be an Avenger, overwhelmed by the sight of the older and experienced heroes before her, a stark contrast to her comic self.
Avengers No More Part 1
- With the destruction of the Stark Expo, the Avengers lose all communication with Tony.
Avengers No More Part 2
- Despite the best efforts of Black Panther's team, they are unable to save the Avengers and are forced to watch as the Avengers disappear without a trace.
The Sleeper Awakens
- Skully's Heroic Sacrifice. When it's all over, Vision just stares at the rubble with a heartbroken look on his face (justified, as he's an android and unable to cry). Back at the Mansion, while the others sit on the couch and talk, Vision just stares out the window looking mopey. At least until Ant-tony comes to cheer him up.
The Once and Future Kang
- By the time Falcon has been found, he spent years in a Bad Future when he's only been gone for weeks, and he's aged into an adult. The fact remains that by the time Falcon returns to the present, he will be a far different one, almost unrecognizable. The happy-go-lucky Teen Genius Falcon we grew accustomed to from the beginning of the series is no more.
- All Avengers are back together, the Cabal has been defeated, but Iron Man still remains unaccounted for.
- The Avengers reaction to seeing Avengers Tower after it was destroyed last season is heartbreaking.
- Just the fact that the Avengers think Tony is dead is really sad, especially from the original Avengers.
- First of all, none of them can actually bring themselve's to say Tony's dead.
- Sam starts to say the tower is "exactly the way Tony designed, before..." and trailing off.
- Steve tells Natasha that after the ice he coped by focusing in his missions and his team. When you take in to account the scene immediately after where he wishes Tony was there while looking at the ground and then raising his chin in determination as they enter the pyramid and you have a pretty clear picture of how Steve's handling Tony's "death".
- A happy Tearjerker, Steve and Natasha discovering that Tony is very much alive. Steve even gives Tony a hug, much to Tony's discomfort.
- Tony and Steve's bickering as the Beyonder tries to tempt Tony into joining his side.
All Things Must End
- Loki's betrayal following the Beyonder's defeat; he even plans to unleash an Eldritch Abomination called the All Dark on everyone and everything.