Question: What do the drummers do? It says they increase moral. What does moral equate to in attack/speed for affected soldiers? Seems like it makes them faster, but not 100% sure. What would be the best use for them?

Answer: 
I wish there was more documentation on this game, but all I could find online was this:

> 
> Drum Solider: can not attack but can increase attack rate and damage
> 
> 
> 

I didn't notice an increase in attack rate, but I did seem to get more critical hits. However, I wasn't rigorous about my observations so take them with a grain of salt.

I'm not sure about the best use, but I often place a lot of Taoist Priests or Hammer Soldiers around one Drum Solider. Also, I know upgrading the Drum Solider (75, 150, 300) increases its range, but I don't know if it increases its effects as well.

Source: [Empire Defense 2 Blog Post](http://android-games-cheat.blogspot.com/2012/07/empire-defense-2.html)
The Drummer can increase the morale of soldiers with 30 or 40 percent. And when it upgrade to the third stage, it can covers more soliders.