We all know that Sati was married to Mahadev against the wishes of her father Prajapati Daksh. When he organised a yagna ceremony and invited all the devtas, Sati firstly felt annoyed but then she thought a daughter doesn't need any invitation to go to her father's house.
Sati went to her father's house but his father insulted Mahadev and she became angry. She took the form of Jagadamba and revealed the power of her and Mahadev. Then she left that body and took her Bhadrakali form and went to Vishnu and ordered him to direct that body into parts so that she can again take re-birth.
Vishnu did as per Bhadrakali's instructions.
The place where the body-parts of Sati falled turned into Shakti-peeth.
Now, Shiv detached himself from the world and went to do tapasya.

Adi-Shakti re-incarnated as Parvati and Vishnu Ji helped Parvati to meet Mahadev.
She took the form of Brahmacharini.
Indradev thought that Mahadev should see that Sati has incarcerated as Parvati.
He Ordered Kamdev to do the job. ...