Forest Spirit is one of the three skins released in the second part of the Troldir's Mystic Shop offer. It could be purchased as part of an item deal in mid March 2018.
Forest Spirit could be purchased for $4.99 in a limited time deal that included 3250 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 second part of the Troldir's Mystic Shop offer was released again for limited times in late May 2020 and then in mid June 2021. The price and included coins for Forest Spirit remained the same for each of these releases.