slight correction, Buddhists are one handed, two weapons folks originally.
The reason why Shintoists incorporated Buddhism is, from what I know, the Shintoists viewed Buddhism as a modern civilization that could destroy Shinto Japan. And thus, the decision to import Buddhism was made. In that essence Buddhism is similar to Christianity, and has many similar traits when compared with ancient religions prior to 2000 years ago. I still wonder why we did not do the same with Christianity.
Shinto to me is kind of like the old testament to me as a story, and I hardly know anything about the stories as it is written in the ancient language. I got a major kick out of reading some translated Shinto texts at this web site. The translator went as far as translating it using the biblical writing styles, while also writing that the victims were sliced open like a melon. In the English translation, I rather got the impression that Shinto was a story about a serial killer, which I find some humor in it.
This is not official Shinto thought, but what I view as ultimate knowledge of the sword is the "sword that activates/alive-ing people". Where as the sword to kill people is called the "murder sword". A number of great swordsmen reached that conclusion, and that is why I view the Japanese sword as the Japanese bible, it is a record of the people of Japan condensed in the manufacturing process and relationship to the Japanese sword.