From Halopedia, the Halo wiki
A lumenon is a species of flight-capable animals, classified as "sky-rays". Native to the Forerunner-colonized world of Rhotero, the lumenon were appreciated by the Forerunners' Builder rate and were commonly placed on refuges created by the Builders as a result, including the planet of Genesis. Lumenon breeding on Genesis has gone unchecked for millennia, though the creatures generally keep their distance from other beings, preferring to hunt sea creatures on the surface of the planet's vast oceans. Lumenon could also be found at at least one Warrior-Servant military compound hidden within a Burn.
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