One year before the beginning of the story. Kaguyama feels intimidated by Haruna’s presence on the baseball team since he feels that his position as the ace pitcher is threatened. Kaguyama wants to quit, but Haruna talks him out of it after telling Kaguyama about his own past. (Source: Wikipedia)

Two OVAs released with the 8th and 10th volumes of the original novel. They fall chronologically between the first and second seasons.

An unaired OVA episode of Kore wa Zombie Desu ka? of the Dead. It is the 11th episode and was bundled with the sixth volume of the manga.

In the backwater town of Bellforest lives a 14-year-old boy named Renton Thurston. He desires to leave his home behind and join the mercenary group known as Gekkostate, hoping to find some adventure to brighten up his mundane life. However, stuck between his grandfather's insistence to become a mechanic like him and the pressure of his deceased father's legacy, the only excitement Renton finds is in his pastime of riding the Trapar wave particles that are dispersed throughout the air, an activity akin to surfing. Everything changes when an unknown object crashes through Renton's garage, discovered to be a Light Finding Operation—a robot capable of riding the Trapar waves—specifically known as the Nirvash typeZERO. Its pilot is a young girl named Eureka, a member of the Gekkostate, who requests a tune-up for the Nirvash. Their meeting sparks the beginning of Renton's involvement with the Gekkostate as he takes off alongside Eureka as the co-pilot of the Nirvash. [Written by MAL Rewrite]