Malladus the Demon (King) is the First Hokage. He was the strongest of the New Order before his death at the hands of the EnderLords. He then became a spirit in his little brother Sonake's belt, before being summoned back as a huge, blue ghost-thing, something inherited from one of his less favorable ancestors, the Demon King of the same name. In this form, he possessed Ender, forcing the rest of The Master League to fight him. He was defeated, and his (Malladus's) shattered fragments were stored inside the Shadow Sphere. Everyone thought Ender was dead, but we all know that Ender cannot die. Not now that he is the last one.
Malladus's soul still roams inside the Sphere, searching for a way to break free.