Famous bearers of this name are Japanese football player of Korean descent Kazunari Okayama (Kang Il-Sung) and Japanese Nippon Professional Baseball player Kazunari Sanematsu.
Other Kanji combinations are also possible.
As a word, Kamui (カムイ), which is normally written as Kamuy (カムィ), refers to a spiritual/divine being in Ainu mythology. Personified deities like Repun Kamuy (god of the sea, depicted as a killer whale or an orca) and Chikap Kamuy (god of the owls and the land, depicted as a great owl) often have Kamuy applied as part of their names.
Bearers of this name include manga artist and character designer Kamui Fujiwara (藤原 カムイ) (1959-) and racing driver Kamui Kobayashi (小林 可夢偉) (1986-).
This name is rarely given to boys, if given at all.