Magnus' Gift is part of the base game. The crafting stations are located in Greenshade (Arananga), Rivenspire (Vaewend Ede) and Shadowfen (Xal haj-ei Shrine). 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.