A manga and an anime called Basilisk (2005) are based on the same novel The Kouga Ninja Scrolls and bear the same character names as in the novel and the movie. Although their characters in the film are highly altered from both the original novel and the manga/anime series.
The story is an adaptation of Futaro Yamada's novel The Kouga Ninja Scrolls, which depicts the clash between two ninja clans, Iga and Kouga, and the fated love between Gennosuke (Kouga) and Oboro (Iga).
The film characters with superhuman powers are considered to be Japanese X-Men due to being outcasts and being born with their own abilities, it is worth noting however that one of the film's inspirations was the novel The Kouga Ninja Scrolls published in 1959 while the first issue of X-Men was released in 1963.
Oboro and Gennosuke are star-crossed lovers in the film though aside from hugs no physical or sexual contact is ever shown between the two, not even a kiss.
Joe Odagiri and Yukie Nakama previously collaborated on Song of the Canefields (2003).