We used to have clear red skies. We used to smelt ore, cleave wood. We used to be a civilization. Then Yod arrived. 
History
Yod was a mysterious inter-dimensional powerful being that abruptly conquered the world where Hecla lived and stripped its inhabitants of their industry and resources, leaving them with only enough to derive sustenance. It was believed he did so to prevent insurgents from rising up.
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Yod's regular form
When Yod arrived to this world's dimension, he found no way back. Due to this, he had a this world's greatest scientist build a device which, combined with Yod's own magic, could teleport a person to wherever it pictured home in its mind.
Years later, when Thor was banished to this very same world by Hydra, Hecla accompanied her to Yod's lair in order to retrieve the device that could return her home. When they reached the top of the mountain where the ruler lived, Yod attacked them, and fatally injured Hecla while he was trying to hand over the device to Thor afte retrieving it from its case. After using the device's last charge on Hecla, Thor lunged at Yod and snatched from him the energy orb that served as his source of power. She slammed the orb with her makeshift hammer and desintegrated Yod.[1]Attributes
Powers
Magical Transformation: When striking an energy orb in his possession, Yod can transform from a regular humanoid creature into giant horned monster.[1]