Silent Killer

There lurks a silent killer. 
He traverses in the shadows.  
Watching your every move. 
Waiting for the moment to strike. 
You never see him coming. 
You never hear him go. 
But you feel his poison flow through you. 
It courses through your veins. 
Your heartbeat pulses it through your body. 
The venom slowly kills your heart and mind. 
There are few cures and they are hard to find. 
This killer goes by a few names. 
You know him as pain. 
You know him as sorrow.