So this is actually a Rioter.
Enter: Cactopus. A writer and by no means a professional voice actor. The dude just loves him some Corki and Kades had gotten wind that he did a mean impression. We were setting up to do a scratch recording session of a bunch of Rioters for all the champs in the game. I sit down at the mix console. Kades is just behind me (having already done his own version of Rumble). Cactopus steps up to the mic and I give him the old "Alrighty, first line, I'm rolling."
Voice acting is a really challenging task for performers. You have to emote entirely with your voice, you have to hit a character and feeling just right, and beyond that you just need a convincing performance.
The second he got done with that first line I turned around and looked at Kades and he had the exact same look that I did, like "What...? That was awesome." To my knowledge he'd never even really mentioned he had the ability...