Rainbirds are a species of white bird. Their arrival in arid Anatoray presages the rare arrival of rainfall in the region.
Rainbirds are able to cross the Grand Stream, a journey which is dangerous even for heavily-armed warships. This behavior was first observed by the Disith, who realized that rainbirds are able to find relatively calm currents of air in the endlessly raging storm. They take full advantage of this in their war against Anatoray: armadas of Disith warships follow in the wake of rainbirds to safely navigate the Grand Stream. Anatoray, lacking the necessary knowledge for the passage, is only able to defend against Disith's assaults rather than striking back.