It took me a little while think of one that didn’t involve a death, because that is something that I talk about later. With little further to do, this scene is:
Berserker’s backstory reveal in Fate/Zero (Heavy spoilers ahead. Don’t say I didn’t warn you)
This is something you need to know at least the passing knowledge of the story of King Arthur and the Round Table. Saber is a female version of King Arthur. It turns out that Berserker is Lancelot. You know, the Lancelot that betrayed Arthur and ran off with Guinevere. This isn’t getting close to the moment of sadness. The truly sad part is that Lancelot did this to get a raise out of King Arthur because King Arthur was the leader that didn’t have any flaws, so she wasn’t that much of a person back then. Lancelot wanted some proof that Arthur was a human, but it didn’t work. What makes this even worse is that fact that this is what lead him to be Berserker and it breaks down Saber’s piety and lawful goodness even more.
So yeah, very Fate like with deep backstories that are long reaching. So maybe death is still a part of it. This is hard.