Kage Kara Mamoru!

Kage Kara Mamoru! (陰からマモル, lit. Mamoru the Shadow?) is a series of light novels written by Achi Taro. The light novels had ended in March 2008 with the release of Volume 12, but as of July 2009, a new series entitled Motto! Kage Kara Mamoru! (もっと!陰からマモル!, lit. More! Mamoru the Shadow?) has started serialization. It features manga and anime adaptations. The main character is Mamoru Kagemori, a ninja who is sworn to protect his neighbor Yūna Konnyaku.