Why do you need to set rendertargets so many times? Why not just:

graphicsDevice.SetRenderTarget(D);
graphicsDevice.Clear(Color.Transparent);

for all sprites:   
{   
    &lt;draw sprite i&gt;   
} 
graphicsDevice.SetRenderTarget(P);
&lt;Draw D&gt;   


RenderTarget2D behavior in XNA
After clearing a barbarian encampment, a pink number appears above the tile where the encampment was. What does this number mean?

Example:

