Demetrius, or Dem for short, is an angry boy. Or rather, he has a lot od strong emotions that he tends to... exclusively show through anger. He's passionate and though he doesn't always show it, he cares a lot about his friends. He had a rough childhood and has learned to solve problems through violence, but inside he really just wants to do the right thing.

For Demetrius's voice, I'd prefer a relatively deep voice. Either rough or smooth, it could really go either way, but it needs to show emotion.