Siege Engineers
Siege Engineers is a building upgrade in Loot Grinder, the free medieval idle clicker.
What it does
It makes each Fortress produce 2× as much loot. (Fortresses produce 2x loot.)
Cost
It costs 600M loot and is a one-time purchase.
Why it’s useful
The more of this building you’ve stacked, the bigger this upgrade’s payoff — it multiplies every copy you own, so buy it once your count is high.