If you loved Donten: Laughing Under the Clouds - Gaiden: Chapter 2 - The Tragedy of Fuuma Ninja Tribe, try Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle
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.

Donten: Laughing Under the Clouds - Gaiden: Chapter 2 - The Tragedy of Fuuma Ninja Tribe

Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle
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 2 - The Tragedy of Fuuma Ninja Tribe, the second film will land in a comparable space — through a different lens.
What Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle is
You're a reclusive war veteran haunted by government experiments and a body that won’t obey, living off the grid one year after a serpent god fell. Your younger brothers arrive with questions, not pity, peeling back layers of a silence you thought protected them. The film ends with the weight of what blood carries, not just in veins but in secrets.