The Sea of a Mysterious Light (妖光の海 Yōkō no Umi) is the twenty-first episode of Ultraman Gaia.
- Ultraman Gaia
- Version 1
- Ultraman Gaia Volume 6 features episodes 21-24.
- The episode gets its name from the light in the ocean that Candea makes.
- This is the first appearance of Team Marlin.