Fortified Defense
Fortified Defense is a synergy upgrade in Loot Grinder, the free medieval idle clicker.
What it does
Every Tower you own boosts your Keep buildings’ output by 0.15%. (Towers boost Keeps by +0.15% per Tower.)
Cost
It costs 1.50M loot and is a one-time purchase.
Why it’s useful
Synergies scale with how many source buildings you own, so they keep getting more valuable as your kingdom grows.