The Blink Monk's ablities have official been revealed, whether they are real or just some sort of cruel April Fool's Joke. The screen shots of the character all include the haunting Urf just as the art spotlight and official reveal did. At any rate, he looks pretty awesome. He "will" be energy based and be the first bruiser that utilizes that resource system. His W and passive also make him look like an extremely viable jungler on paper, perhaps tier 2 or the fabled tier 1.
Check out some more screen shots by visiting the official A New Champion Approaches - Lee Sin post.