Mister Who is a DC Universe villain, and an enemy of Doctor Fate.
Mister Who's real name is unknown. He was born as nothing but a “hopeless cripple.” He was always tormented by his peers while he was growing up. Whn he became scientist, he developed something called Solution Z, which was based on the world’s most adaptive creatures. Doctor Who decided used it on himself so he can become “strong and tall”. Filled with resentment over the way in which he had been treated all his life, Who decided not to share his discovery, but decided to use his new abilities to steal art treasures and surround himself with beauty, and became an enemy of Doctor Fate.