The Full Story Of Ardhanarishvara
Ardhanarishvara is referred to in the Mahabharata is Shiva plus an unnamed female half.
Upamanyu praises Shiva rhetorically asking if there is anyone else whose half-body is shared by his spouse, and adds that the universe had risen from the union of sexes, as represented by Shiva’s half-female form. In some narratives, Shiva is described as dark and fair-complexioned, half yellow and half white, half woman and half man, and both woman and man. In Book XIII, Shiva preaches to Parvati that half of his body is made up of her body.
The absolute origin of Ardhanarishvara can be traced to a story in the Skanda Puran, where Parvati asks to become one with Shiva so this form is created.
Another story in the Skanda Puran is where Parvati is kidnapped by a demon named Andhaka, and Parvati takes on the form of Ardhanarishvara to protect herself.