Raider Invasion

"The raiders have been planning a calculated attack, and are amassing on the boarders of empires far and wide. Prepare your defenses! Clad in the SKULLS of fallen foes, they drop 5x more. So, pound away on the enemy and get your Raider Training Camp and Units!"

- Ikki

Overview
The Raider Invasions are special events. During these events, Raider encounters are 5x more likely to spawn and are more likely to drop Skulls.

So far, there have been 2 Raider Invasion events:
 * February 7th - February 19th, 2012
 * October 11th - October 14th, 2013