West of Corvo Bianco, past the lake with the island on the western shore, you’ll spot a ruin on the map of the Gorgon Foothills.Grandmaster Manticore Witcher Set – Diagram Locations
There are 5 Grandmaster Witcher sets available in Toussaint. All sets consist of 6 pieces (4 armor, 2 swords) - a Side Quest will unlock after finding one set diagram and track all future diagram discoveries.