Sankarea is a romance-horror series where the male lead is obsessed with zombies, and the female lead literally becomes one. The OVA episodes show the before: Chihiro as a kid with a missing mother, Rea as a girl still trapped in her abusive home. These aren't epilogue bonuses. They're the foundation that makes the impossible love story in the main series actually devastating instead of just weird. The show commits to the bit in a way most romance anime won't. Chihiro doesn't want a zombie girlfriend because he's quirky or horny. He wants her because he's already broken by loss. When Rea dies and comes back wrong, it's not a plot twist that makes their relationship cute. It's proof that he was always willing to accept her at her worst. The OVA explains why a story about necrophilia somehow becomes about devotion instead of depravity. The tonal whiplash between comedy, body horror, and genuine tenderness will lose people in episode one. Everyone else will understand exactly why this show matters.

Two OVA episodes bundled with the sixth and seventh limited-edition manga volumes bookend the Sankarea story with comedy, horror and supernatural romance. The prequel is set seven months before the main plot. Chihiro, his father and Ranko travel to Tohoku to help a relative sort a huge pile of books. A familiar bridge makes Chihiro wonder why he recalls so little about his mother, Yuzuna. Among the books he finds her old photo and a strange volume about raising the dead, and at a nearby hot spring he crosses paths with Rea for the first time. Meanwhile Rea, freshly done with middle school, is abused by Aria, her father's second wife, who vents her drunken frustrations on the girl. The second episode takes place after the series. The Furuya family finds a silent, mysterious girl hiding beneath their household temple, and when Rea brings her dinner, the girl pushes her down the stairs.