The "Rubyblossom Extract" is an item that you need to create the Molten War Torte. To obtain the Rubyblossom Extract you need to visit the Tel Var General Merchant in the Imperial City Sewer Entrance, it costs a total of 100'000 Tel Var stones to purchase the item.
Item: Rubyblossom Extract
Cost: 100'000 Tel Var stones
Location: Imperial City Sewer Entrance, Tel Var Stone Exchange, Tel Var General Merchant
Rubyblossom Extract
