When Merida DunBroch died, it was her time. She was old and weary, having lived a full life. She never did marry, choosing to pass the birthright down to her brothers instead. She knew they would lead with a loving hand, and they had yet to prove her wrong. When Merida died, she was born again. She looked a mere 16 in age, her creaking bones being replaced by the well oiled joints she had used to save her mother all those years ago. The Moon comforted her, told her to lead others to their destinies with the wisps that led her to her own.
When Jack Overland died, Merida saw. She saw everything he might have done, everything he could have been if he lived. She could see a loving wife, a happy home, a son and daughter... but at what price? A dead sister, a fractured heart within, and a sweet little girl a bit off into the future who died instead. When Jack Overland died, he was born again. Merida wished she could comfort him. She wished his destiny wasn't Jack Frost, but that was not her choice. Sometimes the Moon knew what needed to be done, and Merida could not argue.
When Rapunzel, Queen of Corona died, Merida saw. She saw how the new princess would grow up motherless, the king wifeless. She saw how the king would become more distant with the passing years. She saw how Rapunzel could have healed the relations between Corona and Berk, how she would have been one of the first kingdoms to fully accept Arendelle after the queen officially revealed her powers to the surrounding peoples. But none of this would come to pass. When Rapunzel of Corona died, she was born again. Merida cried for her as she returned to this world. She wished her destiny wasn't Rapunzel of the springtime, but that was not her choice. Sometimes the Moon knew what needed to be done, and Merida could not argue.
When Hiccup Horrendous Haddock the III died, Merida saw. She saw his full life, with a beautiful wife whom he loved with all he had and who loved him with the same fervor, the best friend one could ever hope for, a son who would lead their people well. And she was thankful. He had been able to have a wonderful life before he was brought to the lonely world of the spirits. But she still cried and wished it was not so, for rather than ascending to eternal peace, he had a new destiny. One even Merida could not fully see. She wished his destiny wasn't Hiccup, Prince of the Dragons, but that was not her choice. Sometimes the Moon knew what needed to be done, and Merida could not argue.
When some were meant to die, they did not. They had too much life left. Their possible destinies too great to leave empty and unfulfilled. When they were meant to die, Merida didn't let them. She gave them the destinies that led them to life. And she was glad, for they lived on. Sometimes Merida knew what should to be done, and she didn't care what the Moon said.