Royal Masons
Royal Masons is a building upgrade in Loot Grinder, the free medieval idle clicker.
What it does
It makes each Keep produce 2× as much loot. (Keeps produce 2x loot.)
Cost
It costs 30M loot and is a one-time purchase.
Why it’s useful
Doubling a building’s output is one of the strongest loot-per-coin investments once you own several of that building.