The In-betweener is a abstract entity (a cosmic force embodying a concept) who "exists as the synthesis of the major concepts of the universe: life and death, reality and illusion, good and evil, logic and emotion, existence and nothingness, god and man." The In-betweener apparently came into being fulfilling the need for a balance between the major forces of reality personified by the disembodied heads of Master Order and Lord Chaos. Even so, his existence was first encountered by Adam Warlock, who was abducted by In-betweener who tried to transform Warlock into a champion of life, restoring the balance of Thanos, self-proclaimed champion of Death.
Later, the In-betweener empowered the wizards calling themselves the Creators, as part of the In-betweener's plan to restore balance in the universe by creating universal insanity. The In-betweener was opposed by Dr. Strange and his masters, Order and Chaos.
Later still, the In-betweener was hatching a plot to destroy Galactus and survive a new big bang, one that would lead to a new reality with the In-betweener in Galactus' role as universal balance. He was soon twarted by the Silver Surfer and allies Mr. Fantastic and the Invisible Woman.
