This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / The Seven Realms Series
The death of Han's family in book one. The corupt Royal Guard keep people from helping!
Early on in book one, Han meets a man who claims to have known Alger Waterlow, the Demon King of legend, and this man insists that Alger was never evil and that Hanalea hand't been kidnapped by him. He says that Hanalea loved him back and he was depicted as evil because the world needed a scapegoat. After The Reveal in book three, it becomes clear that this was in fact the truth, and that the Bayars were a big bunch of arses even back then. Poor Alger was framed for their evil deeds. It also becomes clear that a very scary case of Generation Xerox is going on.