Ayakashi (アヤカシ) is a 2005 visual novel developed by Crossnet. An eroge sequel was later released in 2006 with the name Ayakashi H. A twelve-episode anime adaptation was aired in 2007. A bundle release of the game called Ayakashi Pack was released on December 14, 2007, to celebrate the release of the anime, containing both Ayakashi and Ayakashi H. Ayakashi are parasitic life forms that give their hosts superpowers, but in return, the use of these powers incurs an increasing physical and mental toll on the host eventually resulting in the host's death. Yū Kusaka is a student who lost his will to live after the death of a dear childhood friend. He is brought out of his depression by the arrival of a mysterious girl, named Eim Yoake, and his life is never the same again. Hunted by Ayakashi and their hosts, the power within Yū awakens and a never-ending battle begins.