This article is a fanfic of "Kamen Rider Build". The setting is the new world at the end of TV. The plot follows the story of the TV and stage play. It will use some settings of Ryuuga Gaiden. I firmly refuse to admit that Ryuuga has a girlfriend (yes, I am so angry that I produce my own food). Others in Build still don't remember Usagi Ryu, so some of the settings of Decade and Den-O will be used (for those who haven't seen it, don't worry, I will try to explain it clearly, but I guess this article is just me enjoying myself). The main plot is probably that Rabbit and Dragon try their best to live for each other in the new world. The concept is somewhat similar to the gift of the Magi (the source of the title). The appearance of other characters in Knights only promotes the development of the plot. Original characters may appear later, but they will not become the main characters. This is my first time writing an article, and my writing style is very poor, but I still want to dedicate this shallow article to my favorite Kiryu Sento and Wanzhang Ryuuga!