How do you get hog riders on Clash of Clans?

You need to have the Dark Barracks in order to be able to train Hog Riders and the Dark Barracks are unlocked once your Town Hall reaches Level 7 however you also require the use of the Dark Elixir Storage which you will need to purchase for 600000 elixir in order to build and the Dark Elixir Drill which is the Dark Elixir Collector that you will also need to purchase but for 1000000 elixir.