Tangaroa (Helios II) is a terrestrial planet located in the Helios system, United Empire of Earth (UEE). Highly geologically active, volcanic eruptions are frequent and unpredictable, often giving rise to short-lived landmasses that are reclaimed by the sea. Due to a combination of tidal forces and lower gravity, enormous waves hundreds of meters high are frequent on the planet.
Its few permanent islands are located mostly at the planet's poles. The capital city Mariana is located partially on land and partially under the sea, and is home to a thriving culture of extreme water sport enthusiasts.