Growing up, Thataka knew that she was beautiful. When she came of age, she married Sunda. He was a chieftain that she had previously met. Upon meeting, they had fallen deeply in love, deciding that they would one day get married. Much to their joy, this desire came true. Their union was then further blessed as they had two sons. Thataka's two sons, Mareecha and Subahu, inherited great strength from their mother. As her father was the demigod of valor, strength, and purity, they inherited a great deal of power. Unfortunately, they could not control it.
Though she knew that her sons stood to inherit power from her, Thataka was not expecting the amount that they received. As such, she was not prepared to teach them how to control it. While their powers grew stronger, the boys began to grow arrogant and prideful of their skills. Sunda did not help this, as he thought that they were just acting as boys normally would. In fact, Sunda believed that they were playing much of the time. Because of this, he would often go out and join them in their activities. These ranged from hunting down all creatures in the area, to ripping trees out of the ground in feats of strength.
After a period of time, the saint Agasthya began to take notice of the destruction being enacted by Sunda and his sons. He cursed the person who caused such harm, causing Sunda to immediately die. When Thataka came to rightfully seek vengeance on the person who killed the love of her life, he cursed her and her sons to transform from demigods into demons. Doing this stripped them of their beauty, making their appearances fearful to behold. After this occurred, Thataka was abandoned to her own devices and her sons went to seek other demons. As time passed she grew more and more bitter towards humans. She destroyed the land she dwelt in and killed all who dared to attempt crossing through her territory. It continued in this manner until she was slain by Rama.
(Image of Thataka facing Rama and companions; Image source Wikipedia)
For this story, I chose to retell the story of Thataka by giving more of her background. I thought that she was punished harshly for the actions of her family, and I wanted to make her seem more justified in her response. I felt it was unfair for her to be transformed into what was basically her opposite solely because she grew angry and wanted revenge on the person who killed her husband.
Narayan, R. K. (1972) The Ramayana.