He is the Guardian of the Master Emerald. At one point, he believed himself to be the only living echidna. That was not the case, he met others. He's known to be honest and headstrong, a latter trait that rivals a blue hedgehog. He doesn't take his close friendships lightly. Especially his romantic relationship with Julie-Su. 

Vocally, surprise me. You can do an Elba inspired voice or something different. Heck, surprise me with a different accent. Perhaps an accent from the Caribbean? Go for it.