Achievement: Eliminate an Army by drowning them in a river (including your own…).

This one sounds tricky, but it’s actually very simple once you know the mechanic:
You are able drown one of your own units by collapsing a Temporary Bridge under them.

Step 1: Find a river crossing
Locate a river where a Temporary Bridge can be built.

Step 2: Build the bridge
Order your army to construct a Temporary Bridge (takes 1 turn).

Step 3: Start Capturing the bridge
With your Hero/Army, begin Capture → Raze the bridge.
This will start the countdown until it collapses.

Step 4: Move a (weak) unit onto the unstable bridge
As the Raze takes several turns (4), you can wait until just before the last turn of the countdown to move one of your weakest units onto the bridge tile.

Step 5: End the turn → drown the unit
When you end the turn, the bridge collapses, the unit drowns, and the achievement unlocks.



✅ That’s it! Quick and easy.

• The sacrificed unit must be on the bridge at least right before the last Raze turn finishes.
  
• Use a weak expendable unit to avoid wasting a strong one.
  
• Works with any faction.
  
  
• Currently, trying to leave the unit on the temporary bridge when a monsoon comes and destroys it, does not give you the achievement, as the unit is automatically moved to safety.