Episode 13, when Angemon knowingly sacrifices himself to protect TK and the other chosen children.
Original: Angemon: Sorry, Takeru[...]Surely we will meet again...if that is your wish...
Episode 22, where Matt tells TK he's leaving for a few hours and never returns. TK was in 2nd grade. This could border on nightmare fuel.
That TK and Tokomon split up in the first place, all thanks to DemiDevimon's lies. And then the first sight we see of Tokomon in the episode is collapsed by TK's digivice and crest.
Episode 26, Biyomon wants to protect her friends from their newest enemy, Myotismon, but Sora holds her back and tells her not to or she'll get hurt. Biyomon cries "Sora, why can't you understand me?" Cue Sora realizing that she's behaving like her own mother towards Biyomon, so that this whole time, her mother was always overprotective because she loved her and was looking after her. Biyomon/Birdramon then attacks Myotismon only to be impaled in the chest by Myotismon's attack. Sora cries "Birdramon, no! I love you!" And then her crest of love glows. Made poignant by the fact that Sora's been feeling this whole time like she's never known love and can't truly love anyone. This is also very much a Crowning Moment of Heartwarming.
In The Movie, the part taken from the Digimon: Adventure short film, when Greymon battles Parrotmon. Who doesn't want to cry when two kids are seeing their first Digimon have to duke it out and almost die? Of course, this soon turns into a Crowning Moment of Awesome when Tai wakes Greymon up the same way Kari awoke him (with her whistle), and he kicks that goddamn bird's ass.
When little Kari is crying out for the sacrificed Digimon who just saved her and her brother's life, and Tai's voice connects us to the future story, followed by this. A boy and his digimon.
Her dialogue just as sad in the dub...As Tai wakes up in the middle of the rubble, Kari is already awake, shouting for Greymon to stay.
The end of episode 21: Hikari wordlessly begging her brother not to leave her and his sorrow as he realizes he has to leave her again are nothing short of heartbreaking... the music doesn't help.
The arc that follows, where everyone is separated due to Tai's absence. Joe is stuck buried in debt at a digital world restaurant, Demidevimon drives a rift between TK and Tokomon, Izzy gets stuck in a dark void and is tempted by a Vademon to give up his desire for knowledge (which renders him submissive), Mimi is being waited on by a group of Geckomon and Otamamon and starts to go crazy with power, Matt is struggling to find TK and Sora is the only one who isn't lost, but thanks to Demidevimon she's convinced she'll never truly know love and that her crest will never glow, so she can't bring herself to face her friends (though that doesn't stop her from helping them from the shadows).
Pumpkinmon and Gotsumon's deaths. Although they were technically Myotismon's henchmen, they were only interested in causing mischief and having fun. They even befriend Matt and TK, and when Myotismon himself shows up, Pumpkinmon and Gotsumon pull a You Shall Not Pass to allow their new friends to escape, despite not being anywhere near Myotismon's power level. The english dub claims that Myotismon "banished them to his dungeon", but it's pretty clear he actually killed them.
Gatomon's back story is one giant Tear Jerker. She is accidentally abandoned, waiting all her life for her "special person" only for her to never show up, and then picked up by Myotismon only to be abused and warped into a super-soldier? It's too much.
That has got to be the saddest moment in all of the first season... because he doesn't get better. Since he died on Earth, he was unable to turn into a Digi-Egg.
Oh, most definitely... Especially when he and Gatomon try to hold hands. Her hand passes right through his...he looks sad, and whispers "I'm sorry," before vanishing, leaving her and Kari in tears. The new Digidestined ask who that was, because they, of course, have no clue.
Not really. Remember, time on the two worlds was synced up after the final battle so there was only a couple years between the end of series one and 02, that's not enough time for Leomon to be reborn and digivolve all the way back to Champion level. That's not even enough time to get to Rookie.
Tai's story about how his little sister Kari nearly died because of his irresponsible actions when he was just a kid. What really hurt were Kari's first words back from the hospital: ("Tai.. I'm sorry I can't kick the ball very good. You'll probably never want to play with me again").
Surprisingly, the scene was especially tearjerking in the dub due to Joshua Seth's performance. No offense to Toshiko Fujita, but Seth blew her rendition out of the water - you can really buy the fact that that the poor kid was breaking down in tears, struggling just to talk through the sobbing. This is easily one of the dub version's most emotively powerful parts.
The whole scene is tearjerking in itself, but the whole thing is made worse is the fact that his mother outright HITS him and yells at him like he committed bloody murder (the shot of Tai's mom hitting him is cut in the dub, but the mark it left on his face is left intact). What kid wouldn't be an emotional mess after all of that?
Even that's tear jerking (and somewhat understandable, if very extreme) if you look at it from Mrs. Kamiya's perspective; her son had just made a boneheaded decision that could have easily ended up leading to her younger kid dying. What parent wouldn't feel the need to at least yell at their kid for something like that?
Takeru tricking Pinocchimon into thinking they were going to play, and then bailing on him. He probably thought he finally made a friend, but it wasn't so, and it was his own doing.
What happens exactly makes it moreso; Takeru claims that Pinocchimon has no friends, so Pinocchimon goes off to prove him wrong by…building another puppet out of the junk in his house. While he's gone, Takeru destroys the things he used to screw with the other children. When Pinocchimon finally gets back to show off his 'friend', TK's gone. Something about the way Pinocchimon lets the other puppet fall when he realizes this...
Puppetmon: Cherrymon....what do those kids have that I don't?
Heck, you could probably consider Puppetmon's whole existence to be this. He's probably the most sympathetic Dark Master, because he just wants a friend to play with...the trouble is, he's a psychotic nutcase who's idea of fun involves killing and torture, so it'll never happen.
Don't forget all the Numemon teaming up against Machinedramon, only for all hundred or so to be killed with one punch. As a matter of fact, pretty much anything the Dark Masters do leads to this. Things like Whamon being skewered and Puppetmon's Bad Boss habits won't leave your mind easily.
In Episode 50, it's revealed that the Primary Village has been turned into a wasteland. Seeing Elecmon go from an overprotective Jerk Ass to a massive Woobie is quite a shock.
Episode 51 had both Matt and Sora trapped in caves formed by the darkness in their own hearts. Matt, in particular, was angsting over feeling alone, thinking Tai was a better brother than he was. But Gabumon was able to pull him out of it by reminding him he wasn't alone. Even when Gabumon compares Tai and Matt to ice cream in the dub, the scene can still bring tears.
Matt: I've never let anyone ever get close to me before. Not since my family split up. Ever since then, I've been alone. I figured if my family didn't want me, that I would just keep to myself and never tell anyone what I was feeling, and I swore I would never let anyone see me cry. But, really all I wanted to do was cry. Gabumon: ...Then cry.
Gabumon even starts crying when Matt says that he doesn't matter to anyone, because Gabumon had been waiting his whole life for Matt.
To elaborate: Palmon doesn't want to say goodbye, as she knows it's going to be too difficult; she even hides from Mimi as the latter runs through the forest searching for her. Some Geckomon, however, bring the poor thing out of depression by raising the point that not going to see Mimi off will be worse. So, later, as Mimi's crying on the flying tram car, Sora looks out of the window and suddenly shouts to Mimi to look out the window. And cut to the lone Palmon running, crying and shouting to Mimi. She's then joined by the other partner Digimon in a rousing chorus of Butterfly, acapella.
In the English dub, the ending music is changed to one final, full rendition of "Hey Digimon", which takes on a surprisingly bittersweet tone in the scene.
During the arc with Piedmon, we have Joe's Papa WolfHeroic Sacrifice to get Izzy to safety, which actually leaves Izzy in tears as he gets away. Even worse is the fact that it doesn't work and Izzy still gets captured by Piedmon immediately after.
I am not sure if anyone else feels this way, but in the Digimon Movie when Wargreymon and Metalgarurumon get what looks like killed by Diaboromon and his clones. for those who have watched the entire series up until this point it is heart breaking to see them in such a state
Meta example: Kouji Wada, Japanese singer who performed the opening theme "Butterfly", has passed away in April 3rd, 2016.
On the English side of this tragedy, Paul Gordon who provided the songs for the English dub such as Let's Kick It Up also passed away on February 18th, 2016, just two months before Koji's death.