Anime Fanbooks
- Kyou Kara Maou! Daikenkyuu (今日から㋮王! 大研究?) December 22, 2005 ISBN 4-04-853928-0
- Kyou Kara Maou! Daikenkyuu 2 (今日から㋮王! 大研究2?) December 20, 2006 ISBN 4-04-854073-4
- Kyou Kara Maou! Daikenkyuu 3 (今日から㋮王! 大研究3?) May 28, 2009 ISBN 978-4-04-854355-2
Read more about this topic: List Of Kyo Kara Maoh! Media