Goddess in Buddhism

When I did bit research, I found that. All the Goddess in Buddhism are Demons (**Yesha**) by origin. After getting enlightenment and following from Buddha's teaching, they are transform from Demon to Goddess. For Example: **Hārītī Ajima** who use to kill and feed on human children, become the goddess to protect infant children (Very Interesting Story). I am just interested to know more about Buddhism. I heard there are certain steps or processor that need to achieve to reach such **Divine** stage. So just wondering what are those process or steps called and there definition?? If possible can, someone can share sites with interesting and motivation stories on Buddhism??