Mushoku Tensei: Isekai Ittara Honki Dasu - Eris no Goblin Toubatsu
English name: Mushoku Tensei: Jobless Reincarnation - Eris the Goblin Slayer
Genres: Drama, Fantasy, Ecchi
Type: Special, Episodes: 1
Aired: Mar 16, 2022
Studio: Studio Bind
Source: Light novel
Rating: R - 17+ (violence & profanity)
Synopsis:
Unaired episode included in the fourth Blu-ray volume. The episode will take place during the same time in episode 16 (episode 5 in second cours) and depict what Eris and Ruijerd were up to outside the main story, as teased by the comment "Goblin Extermination."

(Source: MAL News)