Tear Jerker / The Chronicles of Prydain

• The Book of Three
  • Gurgi getting injured, and urging Taran to either kill him or leave him. Taran found the little guy annoying, but can't do it. He says Gurgi is coming with him, and he is going to live.
• The Black Cauldron
  • Adaon's sacrifice full stop. He'd been a great Big Brother Mentor to Taran, and it was wonderful seeing them play off each other. And then he gets shot and dies surrounded by his friends.
  • Taran trading Adaon's brooch for the titular Black Cauldron. It had belonged to the group's recently slain leader, and while he had it, Taran had prophetic dreams and heightened perception that saved them multiple times, earning the others' admiration. He first offers everything else he owns to the enchantresses, and when the companions realize that he means to offer the brooch next, they all each offer their own treasures, only for the enchantresses to turn them down. Orddu even underscores that Taran is giving up something that brought him joy and wisdom for a thing of evil that he intends to destroy before asking if he's sure he wants to make the trade. Afterwards, everyone tries to cheer each other up, with Taran saying the others' treasures meant more to them than the brooch did to him, and Eilonwy telling him that nothing could erase his sacrifice and he could always be proud of himself for it. Then, a few chapters later, he's forced into a position where he does have to keep silent about what the Cauldron cost him and let a Jerkass prince take all the credit.
• The Castle of Llyr
  • Eilonwy destroying the spells and magical artifacts of Llyr and Caer Colur's destruction. They were the only ties she had to her family aside from a couple keepsakes, and the only chance she had to become a real enchantress, but she gave them up to save her friends.
• Taran Wanderer
  • Craddoc's death. Taran had spent months helping him with his fields, believing the shepherd to be his father and thus owed his service, while silently resenting the work and finding out that he was lowborn. When he first sees Craddoc fallen, he first feels relief, that he's been freed from his ignoble life. But he's soon ashamed of himself and rushes to help the shepherd, who tearfully admits that he lied to Taran about being his father, because he needed help on the farm if he wanted to survive. Taran brushes it off and, when he can't bring Craddoc to safety on his own, uses his magic horn with one charge left to call for help from the Fair Folk. He passes out and wakes up in Craddoc's hut, with Gurgi telling him how the Fair Folk saved him. But he's more interested in Craddoc, and Gurgi can only shake his head sadly.
• The High King. Among the highlights:
  • Coll dies and is buried far from home in a barren wasteland.
  • King Rhun is killed while leading a badass rescue mission. We don't even realize he's dying as he spends his last moments excitedly talking about how he's never been in battle before. Fflewddur says that he will write a song about Rhun's mission, that the boy will be glorified as a hero. Taran interrupts him to note that Rhun has died.
  • Fflewddur Fflam destroys his beloved harp and, as one of the Sons of Don, has to leave Prydain forever. Gurgi must also leave with him. Doli and the Fair Folk all withdraw to the underground realms, never to visit the surface world again.
  • The harp deserves a bit more focus. Having been with the reader since the first book, its strings always snapping whenever Fflewddur "colored the facts" (which made it all the more meaningful when they didn't snap, even when it sounded as if his words were exaggerations), it's almost a character in its own right. Even more so, it is destroyed to build a fire to keep the characters warm during a snowstorm—yet somehow it burns throughout the entire night, and as it does so...
    ...as the harp strings blazed a melody sprang suddenly from the heart of the fire. Louder and more beautiful it grew, and the strains of music filled the air, echoing endlessly among the crags. Dying, the harp seemed to be pouring forth all the songs ever played upon it, and the sound shimmered like the fire. All night the harp sang, and its melodies were of joy, sorrow, love, and valor. The fire never abated, and little by little new life and strength returned to the companions.

    Of the harp, nothing remained but a single string, the one unbreakable string which Gwydion had given the bard long ago. Fflewddur knelt and drew it from the ashes. In the heat of the fire the harp string had twisted and coiled round itself, but it glittered like pure gold.
  • Taran refuses to leave his home because he made a promise to Rhun and Coll to take care of their lands. Eilonwy is anguished about having to leave him and uses a ring she has to give up her magical powers so that they can be married. Then Dallben reveals that Taran is actually the rightful ruler of Prydain. He could only reveal it when Taran proved he was worthy of the throne and had gained wisdom.
  • The very end of the series: "Yet long afterward, when all had passed away into distant memory, there were many who wondered whether King Taran, Queen Eilonwy, and their companions had indeed walked the earth, or whether they had been no more than dreams in a tale set down to beguile children. And, in time, only the bards knew the truth of it."