The Icyene are a race of incredibly long-lived winged beings who arrived in Gielinor before the God Wars. The Icyene are generally aligned to the god Saradomin and are some of his most powerful followers. The Icyene conquered and inhabited the area known as Hallowvale during the Second Age along with humans. Meiyerditch became one of Saradomin's most powerful fortresses.
When Zaros, ruler of the area northeast of Hallowvale and other areas such as Forinthry, was dethroned by his Mahjarrat general Zamorak, the God Wars began. Many Icyene were deployed from Hallowvale to help Saradomin in the war. Because trained Icyene have the potential to be extremely powerful, they were very useful to Saradomin's armies.
It is assumed that the Icyene were wiped out during the God Wars due to there being no known Icyene other than Commander Zilyana who was frozen in the God Wars Dungeon when the Edicts of Guthix were put in place.