He is the son of the Whizzer and Miss. America (Robert and Madelyn Frank) who are now deceased. Madelyn had been exposed to massive amounts of radiation when she was pregnant but her powers protected her from the radiation. When she gave birth it was discovered that the baby was a mutant and emitted uncontrollable radiation. The government persuaded the Robert and Madelyn to put their son into a special capsule that would slowly take away the excessive amount of radiation and his aging was also slowed.
Nuklo was created by Roy Thomas, Rich Buckler, and Dan Adkins
The Avengers discovered the capsule decades later. The Whizzer aided the Avengers to try to find a way to contain his son. Eventually Nuklo was permanently cured of his excess radiation problem. He was recently given a place on the Council out of respect to his parents. Nuklo is slow of mind but has passed high school equivalency tests. He is boldly courageous and fiercely loyal to Aubrey and very thankful for having been given a sense of place and belonging. He now is a secret member of the V-Battalion, like his father was. Like Darren Mitchell ( Topspin), Nulko was greatly affected by Ameiko Sabuki's ( Goldfire) death.