This was it, Kagami supposed. The end of him… and the end of the nine worlds if he didn't succeed. He could feel Kaguya leaning against him, warm and hopeful and optimistic and so wonderfully alive. This was all worth it, he knew, for her. For his darling baby sister. He wished that he could tell her good-bye, but he knew that he could no longer speak. And yet, somehow, his sister could hear him. She could hear his good-byes, could hear his reassurances. And that was all that he needed. He had merged with Gold some time ago, right after he died, he remembered. Gold had given him the ability to take over that doll for those moments, those precious moments, interspersed throughout the days. He never got to learn and say as much as he wanted to, but he knew that he had gotten his message across. Kaguya knew that her older brother loved her. And she knew that he would do anything to protect her.
Those many weeks ago – it seemed so close in time! – when all the peasants had been killed… that hadn't been entirely the doll. He had taken over partly, cooperating with the doll's orders and programming, and he and Gold had killed any who would dare hurt his – hurt their—precious Kaguya. Gold had been protecting her since the end of the universe, since she was just a bulge in his mother's stomach on that cold, dead world all those years ago. They both wanted to protect her. They both would.
The plan that the travelers had hit upon was risky. It was stupid. It was vaguely suicidal and not at all likely to work. But Gold and Kagami would make it work. They would do anything for Kaguya… for their precious, precious family. The plan would never have worked had Gold just been a living weapon commanded by its owner. With Kagami's essence combined, with his soul merged with it after those many long years of co-existing in that state, though, his will and power had grown, had become their will and power, more than Gold, more than Kagami. Kagami was, really, a living weapon. And Gold was, in a weird way, human. Somehow, though, the combination had resulted in the spectacular change that had sat with Kaguya that – night? day? – and let her know that they would do their best to make sure this insane plan would work. They had, it seemed, become that magnificent golden dragon that traveled time and worlds and the universe itself so easily.
The plan would take Kagami's life – and more. It would steal his soul. It would forever eliminate Gold. There would never be Kagami, or Gold, in any way, shape or form. They would not be reincarnated. They would not be angels, or ghosts, or parts of the universe. They would simply… not be. As if they had never existed, the universe would accept their presence as its sacrifice… and then forget that that presence was ever there. Kagami and Gold – the dragon – would not feel. It would not think. It would simply be in an oblivion, were nothing was. The idea, in Kagami's mind, always appeared as that dead universe, after the collision. Somehow, he didn't mind. He had been peaceful then. Kaguya had come along, and made him happy. She had given him a purpose to live. In spite of all of this, he didn't entirely want to go, didn't fully want to help. He loved traveling through time and space and everything, found an intense pleasure in watching over his sister, his highly prized Kaguya. But he needed to keep her safe. If he did not do this, he would no longer have a sibling to watch, worlds to explore, a universe to traverse. And so, even though some part of his mind, of his very soul rejected the idea, told there would be no happiness or peacefulness or thrill because he would not be, he made the sacrifice. In the end, both Kagami and Gold chose to go.