Use the Searing Cauldron near Ironhead Lake in Iron Marches to combine the Wyvern's Liquid Fire, Elemental Flames, Destroyer's Heat, a Flame Effigy Embers, and a Fire Imbued Heart to create the Ultra Hot Sphere.
Hint: Gathered by looting the Legendary Fire Elemental's chest in the Thaumanova Reactor of Metrica Province with the Thaumanova Flames Siphon in your inventory.
— In-game description
- Found in the Magnificent Chest left by the Thaumanova fire elemental. You must have the Thaumanova Flames Siphon in your inventory to acquire it. The siphon is converted, so it will not be in your inventory after the event.
- Used, along with other collection items, to create the Ultrahot Sphere.