Twilight's Embrace is part of the base game. The crafting stations are located in Grahtwood (Vineshade Lodge), Stormhaven (Windridge Warehouse) and Deshaan (Avayan's Farm). You can craft any armor, weapon or jewelry of this set in any motif style you know, as long as you have 3 traits researched (per item). You can trade crafted pieces to other players. Each set item becomes bound on equip.