First, I am SO going to call this one, but Kessler. 

Yup. Alternate Cole that comes back (somehow) to our world and is directly responsible for 90% of the stuff that happens to Cole. Plus, Sasha, that lady that ran the Reapers, is his GF. I always thought she was a hot girl, putting the obvious mental insanity aside, and with my newfound hearing courtesy of my cochlear implant, I am OBSESSED with the way people sound. Before, I could hear, but I had to turn the volume up, and focus. Now- natural! 

Did the Commander always sound like someone placed the vocal cords of a snake in his throat? 
Kessler has one heckuva voice. 
Arrow's Slade almost sound like he's whispering sometimes
Hollow Ichigo sounds like a T-Rex when he roars
The above comments are an example of my newfound obsession with the way characters and people sound.