Whitestrake's Retribution is part of the base game. The crafting stations are located in Greenshade (Lenalda Pond), Rivenspire (Westwind Lighthouse) and Shadowfen (Weeping Wamasu Falls). You can craft any armor, weapon or jewelry of this set in any motif style you know, as long as you have 4 traits researched (per item). You can trade crafted pieces to other players. Each set item becomes bound on equip.