MakubeX was found in a sack as a child. Only his last name, 間久部 (Makube), is known, for it was written on the bag itself. He later came to be known as MakubeX, the 'x' symbolizing an unknown variable, and his "name" is always written in romaji. MakubeX is a genius hacker, capable of manipulating computers to do whatever he pleases. He was originally taught by Gen but swiftly surpassed him in skill.