Donten ni Warau Gaiden: Shukumei, Soutou no Fuuma
English title: Donten: Laughing Under the Clouds - Gaiden: Chapter 2 - The Tragedy of Fuuma Ninja Tribe
Japanese title: 曇天に笑う＜外伝＞ ～宿命、双頭の風魔～
Type: Movie
Episodes: 1
Source: Manga
Genres: Action, Supernatural
Studios: Wit Studio
Producers: Production I.G, Shochiku, Blade, Kinoshita Management
Duration: 1 hr
Rating: PG-13 - Teens 13 or older

Fuuma ninja clan is a secret ninja tribe that is waiting for the "Orochi" (gigantic snake) to resurrect for generations. Shirasu and his twin brother Ichiu grew up in this viscous environment and this tells how they become the leaders of the clan.

(Source: Amazon Prime Video)