Seen above are two of his other forms, the Ghost Musashi Damashii and Ghost Newton Damashii.
As stated earlier, Takeru was killed by a Ganma, to be specific, the Katana Ganma and Spear Ganma. At some point after becoming Ghost, he will fight the Electricity Ganma.
Shibuya and Narita, monks-in-training at the Tenkuuji Temple, who support Takeru in any way they can, such as reconnaissance; and Yasushi Onodera, the man in-charge of delivering mail to the temple.
Kamen Rider Ghost premieres this October 4th.
[Source: The Ghouly News Tumblr (link 2)]