Tangaroa is an Imperial Ocean World off the coast of the Sephadollion's Sub-sector Kruha within the Segmentum Ultima. The entire planet is covered in a vast sea that reaches downwards to roughly one-hundred kilometers, and has absolutely no landmass above water. For thousands of years, the planet was left alone until a small expedition fleet led by the Inquisition dived into Tangaroa's depths. It was here that they would find a terrible alien species that was - despite the danger they posed - was worth studying. However, that was over seven centuries ago, and since the expedition fleet's departure Tangaroa has been left abandoned.