Human beings are vast, and contain multitudes. Not so the Gods, who by their very nature are archetypal beings: warriors and heralds, tricksters and psychopomps.
From a certain point of view, a god is nothing but her Purviews reflected through these archetypes, refined by Legend. That may or may not be true, but the gods have difficulty thinking or acting out of “character.” Odin is a Leader, a Sage, and a Trickster, but without some fundamental shift in his nature he will never grow to encompass the role of Lover or Hunter. His role is defined, his dominions assigned by myth and the weight of his own Legend. He is a god of sacrifice because he hung from an ash tree. He is a Sage because this ordeal gave him wisdom.
Scions feel the pull of these mythic roles, the ichor in their veins pulled by Legend as the tides are pulled by the moon, but where the gods are defined by the myth cycles that give them form, Scions (at least, Hero- and Demigodlevel Scions) are still very much human, capable of defying their own archetypes or even changing them altogether. A child of Ares might begin her heroic career as a brute warrior in the image of her father, but as she quests and builds her Legend she might grow into a clever tactician, a mistress of the chaos of the battlefield, or even a pacifist who only draws her weapon when there’s no other choice. The summation of a divine being’s Legend, God, Demigod, or Hero, is her collection of Titles. Each title reflects a Deed in her past, dedication to a task, an accomplishment, or authority over a subject. When a Hero acts in accordance with a Title, his ichor responds and grants his efforts Legendary weight. If, in time, he becomes a Demigod or God, his Titles will become the basis of his divine Mantle.