Hell Girl: Fourth Twilight Jigoku Shoujo: Yoi no Togi

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