Olfmeri

The olfmeri, colloquially referred to as the sky leviathan or the space whale, is an elusive and mysterious creature described as an "avian cetacean", placed on several Forerunner installations by the Lifeworkers.

The olfmeri's ability to defy gravity seems almost impossible, given the incredible size and nature of these beasts. A passive species, these leviathans are as large as many species of whale found on Earth and bear striking similarities to the huge aquatic mammals, but with one key difference: while whales on Earth inhabit the planet's oceans, olfmeri are capable of flying through the skies. The biological mechanisms behind their buoyancy is still a mystery to scientists of the Office of Naval Intelligence, though there are no shortage of curious theories.

A joint UNSC–Swords of Sanghelios task force encountered during an expedition to Installation 00 in 2555.

Production notes
The sky leviathan was planned to be featured in Halo 4. It was an enormous flying whale-like creature that would have lived on Requiem. The concept art were drawn by 343 Industries artist Paul Richards.

List of appearances

 * Halo: Hunters in the Dark