Kore wa Zombie desu ka? OVA

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

Season 1, Episode 13:
Haruna is given the task to hold a Spring Festival at the local shrine, in her own magical-Equipment-girl way, of course... Seraphim does not want to be a freeloader at Haruna's and Ayumu's place, so she starts cooking... And a concentration-game contest in the school's main assembly hall pushes Ayumu and Orito to their limits... (Source: AniDB)

Season 2, Episode 0 part 1:
Haruna wants to play more with Hellscythe at a swimming pool.
Season 2, Episode 0 part 2:
Hellscythe's birthday is near! Haruna prepares a birthday party for Hellscythe in her own magical-Equipment-girl-way. What kind of party could Haruna be holding? What kind of birthday presents will Ayumu and gang give to Hellscythe?