Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Tear Jerker: Cyborg 009
The 2001 series
"Tears of Steel" deals with Albert's Backstory and the story of how he lost his fiance Hilda. They were trying to escape East Germany, so Hilda hid in the back of a van while Albert played an ordinary truck driver. Unfortunately, as they were driving through the checkpoint, the guard tried to tell Albert he'd forgotten his licence. Albert panicked and floored it, so the guards opened fire... ...leading to his being severely injured and Hilda dying in his arms.
The same episode also revolves around Tragic Monster 0011, whose situation parallels Heinrich's: he used to be an ordinary man with a wife and child, but was kidnapped and turned into a cyborg. All he wanted was a chance to return home...
0013's situation is just as bad. Seems Black Ghost loves creating Tragic Monsters.
"London Fogs" reveals G.B.'s history: in this continutiy, he started out in a small theater with a closeknit troupe of friends, including his girlfriend Sophie. As they were preparing to perform "Mists of London", he receieved an offer to act at a prestigious theater. Despite his initial reluctance, Sophie encouraged him to go, and that role helped catapult him to fame... but he lost contact with his old friends, effectively abandoning them. When his star fell, he was too ashamed to try and make amends, especially as he spiraled into drunken depression. When the team visits London, he finally returns to the old theater, and discovers Sophia moved on and had a daughter, Rosa, who utterly despises him. She also takes him to see her mother's grave, and when a BG attack coincides with Rosa and her theater group enacting "Mists of London" itself, he tearfully begs her to let him perform the lead role as his late apology to her dead mother. She does, and later she forgives him..
Pyunma getting forced into a Cain and Abel situation in "Goodbye, My Friend".
"A Phantom Dog". Joe adopting an adorable puppy? Yeah, you know that's going to end well. Especially when the whole episode is presented as Joe narrating the story of how they metup until he's forced to put the pup down.
The climax of the Greek Gods Arc, and Apollo's final moments, where he just... gives up after getting revenge for his sister's death.
"The City of Wind". While looking for a lost expedition party led by one of G.B.'s old friends, Joe gets seperated from the others and meets Princess Ixquic. She begs for Joe to save her from her tragic situation, but he can't — especially after 005's forced to Shoot the Dog and destroy the conditions that enable her and Kabrakan to interact with the outside world.
Not to mention G.B.'s utter breakdown after they find the dead explorers. Joe sure doesn't — the way he calls out G.B. in the end over his anger at Ixquic is heartbreaking in and of itself.
YMMV on Princess Ixquic's handling by the script , and specially on Joe being utterly OOC when saying that his long-time friend's that his pain is less worthy than one of a girl he met less than a day ago (which he would NEVER do), but when you look closely, her situation does massively suck. Clingy and all, Ixquic never was evil... just very naive and sheltered due to her isolation, and truly wants to have company. Sadly, people tend to care more about the gold pyramid than her robotic self, and for worse she could NOT control her guardian Kabrakan...What a shame that her chapter was THAT badly done.
"The Night of the Star Festival", featuring Joe's time jump with Arisu and his wish to see his dead mother... never realizing that the little girl he's traveling with is his mother as a little girl.
"Black Ghost Lives", the Whole Episode Flashback detailing the history of the 00-Project. Particularly when the first four cyborgs meet for the first time... because they've all been thrown into a combat test without warning. Not only poor 003 has a Freak Out due to her overloaded senses, but 004's body starts malfunctioning and he collapses in pain, with the other three unable to help
The same episode combines this with horror by showing the other cyborgs being modified and experimented on, along with the revelation that part of what prompted Dr. Gilmore's Heel-Face Turn was being ignored when he protested Geronimo's heart being replaced by an inferior model.
The Psychic Assassins arc. By the end, Phil's prematurely aged himself to death, Gamo's dead, Lina's sacrificed herself to teleport Cain to The Labyrinth, and Mai, the Sole Survivor, fades out of existence because they changed the past.
Joe getting to catch up with his "Old Friends" Shinichi, Masaru and Mary... and finding out they've been turned into cyborgs meant to assassinate him. Naturally, they blame him for this... but still can't bring themselves to kill him. Though Joe begs for them to join their rebellion, Von Bogoot installed some extra insurance: bombs buried in their bodies. When he activates them, they shove Joe away, bid him farewell, and huddle together for a final group hug, exploding right in front of Joe as he screams helplessly.
During the following arc, Pyunma's reaction when he discovers that Gilmore upgraded him while he was unconcious. While Gilmore's reasons for doing so are sound — after all, he saved his life — he chooses poor counterargument by pointing out how much stronger this makes him, getting called out for it.
And how does that same arc end? With Viina and her sisters getting murdered by Von Bogoot — bonus points for Viina dying in Heinrich's arms exactly like Hilda did — and Joe and Jet appearing to burn up in the atmosphere while Francoise's powers means she's Forced to Watch helplessly. What makes this worse is that Jet was trying to save Joe... but didn't have enough fuel for reentry, rendering it a Senseless Sacrifice other than ensuring that Joe wouldn'tdie alone. As poor Joe screams at Jet and pleads with him to save himself.
In "Conclusion: Gods War", the Mind Rape of all the cyborgs at once, being shown their worst fears — that not only are they monsters, but so are all of humanity.
In episode 3, a little girl is critically injured in a fire trying to save her grandpa (who is really the 'God' controlling the giant). As she lies on the ground surrounded by the cyborgs, 004 assures her that her grandpa is fine. The little girl, worried about her grandpa, requests to hear his voice and reveals that she can't open her eyes due to the fire damage. 004, distressed, says that he's not sure if he can do that and the little girl asks if she could at least hear her grandpa's music. In the background, 007 begins to play her grandpa's accordion, tears streaming down his own face. The little girl expresses her delight, thinking that her grandpa's still alive, and then dies.
Episode 18 of the '79 series, "The Vampire Within Us", sees a town launching a vicious Vampire Hunt. Shortly after the cyborgs arrive, they try to save a couple from being killed by the mob, only for the Mayor to come out and shoot them both dead, then insist he did what was best for the village.
This isn't the first time he's killed, either. In the past, he murdered his son's best friend after he was accused of being a vampire, burning his house down — with the boy's father inside as well. The father survived and turns out to be the Villain of the Week, faking a vampire outbreak in order to force the mayor to kill his apparently vampirized son. And the reason Jim was mistaken for a vampire? He was trying to help a girl who'd been bitten by a snake.
Episode 19 of the '79 series delves into Gilmore's past and how he used to be friendly rivals with two fellow scientists. A summons to meet them on a manmade island turns out to be a trap, and the one responsible reveals that their mutual Love Interest died long ago. Though he'd married her after Gilmore disappeared to join Black Ghost, their bliss came to a premature end when she got in a fatal car crash. Blinded and on the verge of death, she accidentally confessed to her husband that she'd always been in love with Gilmore.
G.B.'s Backstory in the '79 series. He used to go on frequent hiking trips with his best friend, another actor named Henry Brown. The two competed for the lead role in a major production; when Brown won, he encouraged G.B. not to give up on his own career. The two then went on a climbing expidition together, but a sudden equipment failure led to Brown falling to his death before G.B.'s eyes. Due to the timing, everyone suspected he'd killed him out of jealousy. That effectively destroyed his career, causing him to spiral even further into drunken depression.
Episode #2 of the 1968 series...You actually would be quite surprised.
And the episode of the 1968 series where Albert befriends this German girl named Leena, who is actually a Robot Girl, whom her father/creator wants to use as a Soul Jar for the soul of Adolf Hitler. He manages to save her, but he cannot stay or bring her along, and Leena is left at the train station morning how she couldn't tell him that she loved him.. Holy shit, the end is sad.
The deaths of the 0010 twins if you really think about it. They're brothers, but they're never able to touch or else they'll die (being opposite polarities, if they made contact they'd short-circut). When Joe and Ivan trick them into thinking Joe's on the roof of a building, they crash into each other and short-circut themselves to death...and in their final moments, they're holding hands. Pretty sad and almost touching way to go for a couple of Jerk Ass villains.