Odoryuk is the Guardian of Life. In most of his appearances, he looks like a small pony-sized unicorn who wears a red scarf. In Wild Arms 4, Odoryuk was known as Code O and took on the form of a long majestic white dragon as dragons appear in Eastern mythology. In Wild Arms 5, he has a non-elemental TF System tower named after himself, known as "Tower O". In all of his appearances, Odoryuk heals, cures status ailments and revives the party.
Wild Arms/Wild Arms Alter Code F
Wild Arms 2
Tim Rhymeless has this medium equipped when he joins your party.
Wild Arms 4
The Guardians of Wild Arms 4 are different than the rest of the series. They are less like deities and more like ancient and powerful programs that only certain people can access and seem to be devoid of personality or intelligence. Yulie Ahtreide can summon Odoryuk in battle if she is standing on a HEX with a non-elemental (white) leypoint on it.
Wild Arms 5
In WA5, Tower O can only be accessed after deactivating the four previous towers G, F, S, and M. There is no element associated with this tower.