Yelmalio was a son of Yelm, born high amongst the mountains. He fought many gods during the Darkness, after his father had been slain.
Once, Yelmalio went to the Hill of Gold and met Orlanth, who had killed his father. Rather than attack Orlanth, who was his cousin, Yelmalio held out the hand of friendship and forgiveness and gave Orlanth his Lightning Spear in exchange for Orlanth's vow of support. A little later, Yelmalio met the god Zorak Zoran and fought the slayer of Flamal. Unfortunately, the darkness god was stronger and dealt Yelmalio a great wound which allowed his fiery powers to bleed away. Orlanth saw the deed and raced to protect his new friend, chasing off the Berserker God. He took the injured god, no longer of the Fire Tribe, to his stead and made him a part of his household where he was known as Elmal.
Yelmalio was Orlanth's Steadsman. When Orlanth left on his Great Quest, Yelmalio stayed behind to guard the Stead. He led the militia and guarded Orlanth's horses. He wed Ernalda, Orlanth's wife in order to protect her.
The cult of Yelmalio was important where Orlanthi rode horses and where Orlanthi needed militia training. Occasionally, rivalry between the horse-riding Orlanthi and the foot Orlanthi arose, where the horse-riders left their kin.
The Mountain Sun is a cold sun, giving light but no heat. Often hidden by mountain cloud, the Mountain Sun will occasionally burst through the clouds, because Orlanth allows him to shine upon the ground. In recognition of this Yelmalio grants his worshippers the spell of Cloud Clear.
When present in the Darkness, Yelmalio shone as a beacon to his followers. He gives the spell of Sunbright in remebrance of this. He also gave his worhippers the spell of Catseye to enable them to see and not be afraid even when he was not present.
When Yelmalio used his mirrored shield, he could reflect light to dazzle opponents. He grants the spell of Lantern to his worshippers.
Cult members may not learn fire-based magics, because Yelmalio left the Fire Tribe when he lost his fire powers.
Initiates may learn the skills of Spear, Bow, Riding, and Shield Parry. They may learn the spells of Light, Lightwall, Detect Gold, Co-ordination and Repair.
Light Sons are the cult rulers. They may ride no animal but horse, may marry none but an Earth cultist, to reunite Sky and Earth and to restore Yelmalio's marriage with Ernalda and may not eat eggs out of respect for the slain sun.
The wife of Yelmalio grants her husband the spell of Bless Crops.
The god of birds is Yelm's Son. Vrimak grants his brother the spell Speak to Birds.