I loved history in my school days, and I have always been a voracious reader. But in India, you end up doing MBA, engineering or medicine.
No disrespect to any other god, but Shiva's an outsider god. He breaks the rules. He's a brilliant musician, a brilliant dancer; he treats his wife as an equal, and she opposes him many times, but he obsessively loves her.
If you have to write a fictional adventure to convey a philosophy of evil, the best person is the destroyer of evil himself, Lord Shiva.
I turned atheist in the '90s when India went through troubled times - communal riots, bomb blasts... Mumbai, where I live, was badly affected. I blamed religion; also, extremists on both sides - right and left.
A bad book and good marketing won't work, the same way a good book and bad marketing will also not work. There is no choice in the matter that if you need to write a good book, you also need to have good marketing for it.