WMG: The Care Bears Movie

The Spirit in the Book is a Tzeentch Daemon from Warhammer.

Hmm. A sentient book of spells that instantly makes you into a sorcerer and corrupts its user with promises of hope and change? Sounds like Tzeentch's modus operandi.

The Spirit in the Book is some form or association with Satan.

Unlike the other villains who were either incompetent or misunderstood, the Spirit in the Book seems fully aware of how her powers are causing social chaos and seems perfectly ok with having the bears being killed by one of her spells. She also has a more darker feel than most of the villains.