What role does Breanna's Heart (Kree Dawn) play in Stone of Destiny?

Her Heart becomes an active presence bound to Breanna, deepening her obligations and linking her actions more directly to long-term consequence. As a non-corpreal sentient goddess created by Danu and cast into a heart-shaped ruby, Kree Dawn has the power to claim Erin's Hero, and she can inspire those support her Hero into making heroic acts possible.