Hell Girl Enma Ai and her group return for another series to continue their task of transporting cursed people to hell. New questions arise when a previously unseen girl dressed in green appears before them. As her appearances grow more frequent the mystery behind her purpose is gradually revealed even as the task of carrying people to Hell continues.
 
(Source: Anime News Network) 
 
Episodes 7-12 are rebroadcast episodes from previous seasons with minor edits. Episode count does vary for home video and streaming releases. 
7: S1 Ep3 
8: S1 Ep6 
9: S1 Ep12 
10: S2 Ep12 
11: S3 Ep2 
12: S3 Ep9

Episode 1 - Can't Be Seen, Can't Be Heard

Episode 2 - There's Only You

Episode 3 - Someday, Somebody Will…

Episode 4 - Bury Me Deep

Episode 5 - I Can Hear the Song of the Wind

Episode 6 - Twill

Episode 7 - The Tarnished Mound

Episode 8 - Early Afternoon Window

Episode 9 - Spilled Bits

Episode 10 - Black Rut

Episode 11 - A Bird in a Cage

Episode 12 - Stray Inari

Studio DEEN

Hell Girl: Fourth Twilight