Bill Cipher

Bill Cipher, also known as William Mischief Lucipher, is an interdimensional deity. He is the god of chaos and hails from a now-destroyed and unknown 2D dimension. Not much is known about his backstory. His henchmen (known as Henchmaniacs) are also other interdimensional misfits.
His unclaimed territory between realms is in the midst of collapsing, and he is in need of a new dimension. Earth, with its very weak interdimensional barrier, was the perfect candidate. Bill seeks to bring upon Weirdmaggeddon and rule the Earth.