John Stone is a spy, although which nation he ostensibly works for is uncertain. He has worked in the shadows over the years, fighting strange menaces to the Earth with devices of incredible technology.
Stone met and quickly allied with Elijah Snow, the founder of *Planetary*, in 1969. Snow killed The Bride, a cyborg terrorist who was attempting to escape Earth into the Bleed, the interdimensional buffer zone between universes. For many years after that, Stone and Snow shared information and worked together. When Snow was trying to reconstruct his memory after Randall Dowling's "surgery," he came to Stone.
What Snow did not know was that Stone had been working for Dowling, and The Four, since at least 1965. In return for his help, The Four halted his aging and provided him with extremely advanced technology. Still, Stone was uncomfortable working for The Four and did his best to help Planetary subvert them.
Stone was recently freed of The Four's influence by the removal of the bomb they had implanted in his heart, as well as by the death of Randall Dowling. How this will affect the halting of the aging process, or Stone's career as a spy, is unknown.