She is one of The Travelers and worshipped as the protector of the dead and guild of lost souls. Her custodians are mostly paladins and clerics with the grave domain, they travel throughout the core searching for necromantic hotbeds to cleanse and lost souls to guide along the path.
Legends say she was born on Hadira in the Dwarven Hammer clan where she became a strong warrior and leader. After Nightfall she led her people into the mountains and founded a village, later called Diesa's Rest. In order to protect her people against the dangers of Nightfall she volunteered for the mission to bring the fight to Areth. Together with the other Travelers she set out on their quest to break Areth's hold on their world, during which they learned to travel the void and saved Goblin World where she has since been worshipped as the doomed god who protects travelers who've set out on the final journey. She died saving her family and friends in Diesa's Hold from an assault by one of Areth lieutenants, a horned devil called Barael who was eventually slain during The Reckoning.