Kernite is an NPC.
Watwatwaaat? I look like a Frog? I'll put on my new boots and boot you all the way to Pandala! You won't like that, believe me... Pandala is on the other side of town, heeee! Didn't even know that, did you...ohhh people are so stupid, I know just the thing for your kind! Pathetic little so...!
His name is derived from 'Kermit', the Frog in Frank Oz' Muppets.