If you loved Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle, try Donten: Laughing Under the Clouds - Gaiden: Chapter 2 - The Tragedy of Fuuma Ninja Tribe
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
You already loved

Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle
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Donten: Laughing Under the Clouds - Gaiden: Chapter 2 - The Tragedy of Fuuma Ninja Tribe
What they share
Both films are directed by Tetsuya Wakano, and they sit in Action / Adventure / Animation / Fantasy territory. If that's the register that drew you to Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle, the second film will land in a comparable space — through a different lens.
What Donten: Laughing Under the Clouds - Gaiden: Chapter 2 - The Tragedy of Fuuma Ninja Tribe is
You grow up in a secret ninja tribe awaiting a legendary serpent's resurrection, but darkness falls on your clan. The film leaves him marked by tragedy.