Whose greyscale face is on the kappa emoticon on Twitch?

The story behind the answer

The greyscale “Kappa” face is Josh DeSeno, a developer at Justin.tv (which became Twitch). While building the chat system, he added his own headshot as an emote, and it evolved into Twitch’s signature symbol for sarcasm, irony, and playful trolling.

“Kappa” is named after a mischievous creature from Japanese folklore—fitting for an emote that signals “I’m joking.” Memory tip: Kappa = “kidding,” and the face is Josh from Justin.tv—J to J.