First episode is a tale about another boy discovering that he is an ajin. He is actually more realistic and interesting than Nagai is, which is a shame, because this episode is the last we ever see of him. He would have been a far better main character than Nagai. Second episode is worse than the first one. It's first half explains how Sato got to the funds for buying all the weapons he uses. It's a little bit unconvincing since Tanaka is being played like he is a complete moron, which is too much even for someone like him. Second half of the episode iscentered on Nagai and the others fighting Sato at the time of second season. It's basically a filler part of a filler episode, it's less serious and is just a nice addition to the fans and nothing more.

Overall, OVA episodes are nothing special. They, however, still are an OK watch for the fans of the series. 7/10!