The Box is an alternate version of Jerome Johnson, son of the second Jack in the Box, from a timeline where Jack-in-the-Box had died leaving his son an orphan.
History
Box is the son of Zachary Johnson (Jack-In-The-Box II) from a possible future. Zack died before Box (whose real name is unknown) was born. Upon discovering his dad was a superhero, he decided to live up to his legacy. As such, he turned himself into a cyborg to become a superhero. However, he found the amount of crime (even when he was killing people) was overwhelming. Blaming Zack for “failing” to stop crime, (but mostly because he had no had stayed with him), Box went back in time to murder Zack. He teamed up with Jackson (the same son of Zack, but from another possible future) to kill Jack-In-The-Box II. However, Zack managed to capture him with a magnet (due his Box’s implants) in a junk yard. After being sent to prision, the effects of the time travel wore off and was sent back to his time, leaving the present day Jack with a dilemma to deal with.
With the eventual birth of Jerome Johnson and his choice of becoming a medic, it is most probably than the timeline than spawned Box has been erased.
Powers
Box has cyborg implants that gives him super powers. He can extend his legs in a similar manner of Zack’s “footapaults”. He has a robotic arm that can he strech and retract into a box where his shoulder should be. At the end of his arm is a puppet “Jacky Justice”. Jacky seems to be able to change whatever weapon it is holding (as his weapons changes between panels).