SILVER LINK.
In June 2012, an original net animation (ONA) was announced by "Monthly Big Comic Spirits". The ONA is produced by Silver Link and directed by Masashi Kudo. 20 episodes of 3 minutes each were launched from August 3, 2012 to January 5, 2013. It was later broadcast on AT-X and released on two Blu-ray sets on March 26, 2014.