Death Eater to Spy to Potions Master to…Father?

Voldermort was killed the first time around by Dumbledore, not Harry Potter. With the war being over and Severus is no longer a spy he only spied for a year or two , he can finally do something he's always wanted to do: become a father. Warnings: does not follow the books, mentions of abuse, good Malfoys, eventual slash. And I'm not putting any pairing until later.