FASTENING Anime Details and Episodes Music video featuring art, direction and animation by Kawasemi for the song FASTENING by Zutomayo. Series info · Watch free · Trending anime · Airing schedule FormatMusicStatusFinishedEpisodes1Duration3 minScore62/100SourceOriginalCountryJapan Kan Saete Kuyashii wa (Shared Characters) DARKEN · STUDY ME · Seigi · Can't Be Right · Into the Night Uniguri (Supporting)