The third film in the hexagon project J-horror Theatre. The two first films are Kansen (2004) and Premonition (2004).
Takako Fuji portrays the hotel maid. She had previously collaborated with Takashi Shimizu on the Ju-on: The Grudge (2002) series and the American remakes known as Der Fluch - The Grudge (2004).
(at around 42 mins) During the first scene in the hotel when Nagisa attempts to hide from Professor Omori, she first attempts to enter a locked room 237. This may be a reference to Shining (1980).
"Reincarnation" was the Brazilian Portuguese title chosen for Birth (2004), released the year before. Thus, this film was titled "Reincarnated Souls" in Brazil.