In an official announcement by the publisher Media Factory, it was announced that Yamaguchi Noboru
, author of the light novel "Zero no Tsukaima
" passed away on April 4th at age 41 after more than two years of fighting cancer.
Yamaguchi debuted as a novel writer in 2000 by writing for Kadokawa Sneaker Bunko. He later moved to MF Bunko J and published "Zero no Tsukaima" in 2004. Altogether, the incomplete series includes 20 volumes of the main novel and 5 volumes of spinoff novels. The full series of the light novel also got adapted into 4 seasons of anime.
Source: Media Factory official announcement