Champion is one of the two skins released in the Champion's Trial offer. It could be purchased as part of an item deal for a limited time in December 2016.
Champion could be purchased for $4.99 in a deal that included 7000 coins. It could also be purchased for $19.99 in the “Best Deal!” which included the Jotun skin and 50000 coins. This skin was not available for individual purchase and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: The Champion's Trial offer was released again for a limited time in mid April 2019. This time the deal that included 7000 coins was reduced to 3250 coins at $1.99. The Best Deal was lowered to $9.99 and the included coins were reduced to 30000.