Night Hunter is one of the six skins released under the Moonlight Festival offer. It could be purchased as part of an item deal in late October 2017.
Night Hunter could be purchased for $19.99 in a deal that included the Wendigo skin and either 50000 coins (Browser) or 1800 DNA (Mobile). It was not available for individual purchase and may not be available for purchase in the future.
Details of this offer may vary depending on location and platform.