Senjuushi: Kijuushi-tachi no Happy Birthday!
Japanese title: 千銃士 貴銃士たちのハッピーバースデイ!
Type: OVA
Episodes: 1
Source: Game
Genres: Action
Studios: TMS Entertainment
Duration: 24 min
Rating: PG-13 - Teens 13 or older

The story will be about the characters celebrating their master's birthday, which happens after the sixth episode.

(Source: MAL News)