This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / The Legend of Spyro
The ending of The Legend of Spyro: Dawn of the Dragon. After defeating Malefor, the world starts to crumble beneath Spyro and Cynder. Before falling away, Cynder and Spyro help recombine the world, with them as the cost. Right before the credits roll, you get one simple message: "Thank You for helping us complete this series, without you it wouldn't have happened", followed by the credits playing with the absolutely heartwrenching song, "Guide You Home (I Would Die For You)". For those who grew up with the series, it's definitely depressing to see Spyro die. Thankfully, it was a Disney Death, and Spyro and Cynder are still alive. Still, it's one big punch in the gut to see the "Legend"-verse of Spyro at its end.
Ignitus' story about Cynder's past, if the fact an entire generation of unborn babies was just slaughtered doesn't do it, what was done to Cynder certainly would.
Also, Cynder's explaination at the beginning of The Eternal Night, she's leaving because her past is hurting her so much she can't stand staying somewhere she clearly enjoys being, it's clearly hard for her to leave but she feels she has to. Worse, it's not her fault at all. She's an innocent victim and blames herself for 12 years of murder and destruction she was forced to cause, and is just a poor little kid!