Question

who is the father of mahadev​

Answer 1

Lord Shiva replied that Brahma is his father.

Answer 2

Once Naradmuni Asked Him That Who Is Your Father He Said 'Vishnu' And When Naradmuni Asked The Same Question To Vishnu He Said 'Mahadev is My Father'

So We Can Conclude That The Three Main Gods : Brahma Vishnu Mahesh Created Themselves Only Their Origin Is Not Defined