Is that Vitalik sitting on the horse? 
That is what it seems like. But, as per suggestions given in their Telegram group, we have to focus on the Whitepaper. I suppose, Vitalik wont help us in this hunt. 
C'mon guys, that's not Vitalik sitting on the horse, horses don't have a horn... That's a Unicorn!
We can say is Vitalik sitting on the Unicorn holding a Unicorn... And the unicorn is Mining ETH on each step.
I only hope this puzzle isn't fake.